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APPENDIX 1: UNITS
The basic SI units needed in this text are based on the following fundamental quantities shown in Table Al.l
Table Al.l
Quantity
Length
Mass
Time Temperature Angle Electric current
Sf unit
metre, m
kilogram, kg
second, s kelvin, K radian, rad ampere, A
Other common units
1 gram= --kg
1000
oc degree
The units associated with other quantities are based on the fundamental quantities shown in Table A1.2.
Table A1.2
Quantity Sf unit
Velocity ms-1
Acceleration ms-2
Force Work, energy Pressure Density Electric charge Electric potential
newton, N joule, J pascal, Pa kgm- 3
coulomb, C volts, V
Relationship to fundamental units
N = kgms-2
J = Nm = kgm2s-2
Pa = Nm-2 = kgm- 1s-2
C =As V = J/C = kgm2A -ls-3
483
484
APPENDIX 2: MATHEMATICAL FORMULAS
PROPERTIES OF EXPONENTIALS AND LOGARITHMS
log(xy) = log x + logy
log (;) = log x - log y
log(xn) = n log x
QUADRATIC EQUATIONS
If a~ + bx + c = 0 then
x=-----2a
THE BINOMIAL THEOREM
For n a non negative integer
where
n! nc =----r (n - r)!r!
For n a real number and I x I < 1
n(n - 1) n(n- 1)(n- 2) (1 + x)n = 1 + nx + x2 + x3 + ...
2! 3!
ARITHMETIC AND GEOMETRIC PROGRESSIONS
For an arithmetic progression with first term a and common differenced
nth term tn = a + (n - 1)d, and
Sum of n terms Sn = n/2[2a + (n - 1)d)
For a geometric progression with first term a and common ratio p
nth term tn = apn-l, and
a(1 - pn) Sum of first n terms Sn = --'----'-..:....
1 - p
If I p I < 1 then
a Sum to infinity Soo = --
1 - p
DIFFERENTIATION
General rules
The chain rule
dy dy du -=-·-dx du dx
Mathematical Formulas 485
486 Foundation Maths for Engineers
The product rule
dy dv du y = uv ~ - = u- + v-
dx dx dx
The quotient rule
du dv v--u-
u dy y = -~-=
v dx
dx dx
Some useful derivatives
Note in the following table a and b are constants
dy y
dx
a 0
X 1
xn n~-1
axn anxn-1
smx COS X
COS X -sin x
tan x sec2 x
sec x sec x tan x
cosec x -cosec x cot x
cot x -cosec2 x
ex ex
1 In x
X
sin(ax + b) a cos(ax + b)
cos(ax + b) -a sin(ax +b)
eax+b atfx+b
a ln(ax + b)
ax+ b
INTEGRATION
Some Useful Integrals
Note in the following table a and bare constants and cis an arbitrary constant.
Jadx=ax+c
f xn dx = - 1- xn+l + c, provided n ;1'- -1 n + 1
f a~ d.x = _a_ xn+l + c, provided n ¥- -1 n + 1
J sin x dx = -cos x + c
J cos x dx = sin x + c
J; dx =In x + c
J sin(ax + b) dx = -;cos (ax + b) + c
J cos (ax + b) dx = ~ sin (ax + b) + c
f eax+b dx = ; eax+b + c
J --1- dx = _!.In(ax + b) + c ax+ b a
Mathematical Formulas 487
488 Foundation Maths for Engineers
J __ 1_ d.x = _1 tan-1 (-bx) + c a2 + b2x2 ab a
Integration by parts
General logarithmic form
J f'(x) - d.x = ln[f(x)] + c f(x)
Numerical or approximate integration
In the following the interval of integration is from x = a to x = b. This interval [a, b] is subdivided into n equal subintervals/strips.
Each strip has width h = (b - a)/n.
x0 = a, x 1 = a + h, ... , Xn = b
Yo = f(xo), Yt = f(xt), ...
The trapezium rule
rb h Ja f(x) d.x = 2 [yo + Yn + 2(yl + Y2 + · .. + Yn-t)]
Simpson's rule
rb h Ja f(x) d.x = 3 (yo+ Yn + 4(Yt + Y3 + · · · + Yn-l)
+ 2(yz + Y4 + · · · + Yn-z)]
NUMERICAL MATHEMATICS
The Newton-Raphson Iterative Method for approximating to a root of f(x) = 0.
Let the nth approximation be Xn and the (n + 1)th approximation be Xn+b then:
TRIGONOMETRIC IDENTITIES
Basic definitions 1
cosec 9 = -sine
1 sec 9 =-
cos 6
1 cot 9 =-
tan 9
Pythagorean formulas
cos2 6 + sin2 = 1
1 + tan2 6 = sec2 9
cot2 e + 1 = cased 6
Addition formulas
sin (A ± B) = sin A cos B ± cos A sin B
cos (A ± B) =cos A cos B + sin A sinB
( tan A ±tan B tan A ± B) = -----
1 +tan A tan B
Mathematical Formulas 489
490 Foundation Maths for Engineers
Double angle formulas
sin 28 = 2 sin 8 cos 8
cos 28 = 2cos2 8 - 1 {
cos2 8 - sin2 8
1 - 2 sin2 8
2 tan 8 tan 28 = 2 1 - tan 8
1 sin2 8 = - (1 - cos 28)
2
1 cos2 8 = - ( 1 + cos 28)
2
VECTORS
Two dimensional vectors
Magnitude
If a = a1i + a2j then
I a I =a= Yay+ a~
Three dimensional vectors
Magnitude
If a = a1i + a2j + a3k then
I a I =a= Yaj +a~+ a~
MATRICES
2 x 2 matrices
Identity matrix
I= [~ ~]
Determinant
If
then
I ac db 1--ad-bc det A= I A I=
Inverse
If
A= [ ac db] and det A ¥= 0 then
1 [ d -b] A-I---det A -c a
Mathematical Formulas 491
492
ANSWERS TO THE EXERCISES
CHAPTER 1
Exercise 1.2.1 (a) I e I e I . X (d) e I I I. 1. -1 0 1 2 3 4 5 -3-2-1 0 1 2 3
(b) I. I • I • X (e) • I I I I -1 0 1 2 3 4 5 -4-3-2-10 1
(c) • I I • I • X (f) lei I I lei -2 -1 0 1 2 3 -3-2-1 0
2. (a) -3 ~X~ 2 (b) -1~t<5 (c) -0.2 < u < 0.3
Exercise 1.2.2
1. (a) x > -3 and x > 1 so -3 < x < 1 (b) X< -3 and X> -6 SO -6 <X< -3 (C) X ~ -2 and X ~ -3 SO X ~ -2
Exercise 1.3.1
1. Independent variable- resistance; dependent variable - current
Exercise 1.3.2
1
1. (a) Daylight hours (b) Amount of petrol
Jan Dec Distance
Months
(c) Atmospheric pressure
Height
2
1e 2 3
.. X
"' X
..
Time
Answers to the Exercises 493
Exercise 1.3.3
y
(3. 3)
X
(1.5.-3)
Exercise 1. 3.4
80 ~ .. ., 0 -g ~ " 0
E 40 "0 .g "' c..
Distance (thousand million km)
Exercise 1.4.1
v (a) 6 (b) v
(c) Extension
4 2 200
2 100
0 2 X 100 200 300 T 100 200 Mass
494 Foundation Maths for Engineers
(e) Speed
60
(d)
40
20
5 10 Voltage
Exercise 1.4.2
1. (a) 3/3 = 1 (d) 1/4 = 0.25 (g) 1/2 = 0.5
Exercise 1.4.3
1. y
(0,1) 0
2
y
8
6
4
2
0
(b) 1/3 = 0.3 (e) -1/2 = -0.5 (h) -2/5 = -0.4
y
gradient 3
0 X
y
(0, 4) 4
3
2
0 gradient -3
2
2 4
(c) 6/6 = 1 (f) 1/5 = 0.2
6 Time
(i) -1/4 = -0.25
X
X
Exercise 1. 4. 4
1. (a) 1 (b) 3
Exercise 1.4.5
1. Graph Gradient
(a) 2 (b) 0.0033 (c) 0.67 (d) 0.33 (e) -9.8
Exercise 1.4.6
1. Graphs in Figure 1.17
(a) y = x + 4 (b) y = 1/3 X + 4 (c) y = x (d) y = !x + 3 (e) y = -ix + 7 (f) y = 0.2x + 2 (g) y = 0.5x - 2 (h) y = -0.4x + 3 (i) y = -!x- 1
Exercise 1.4.4
(c) 6 (d) 4
Intercept
1.5 0.85 0.0 0.0
70
(a) y = x + 1, y = 2x + 1, y = 3x + 1 (b) y = !x + 3, y = ~X + 3, y = ~X + 3 (c) y = -x + 6, y = -2x + 6, y = -3x + 6 (d) y = -jx + 4, y = -!x + 4, y = -~x + 4
Exercise 1. 4. 7
1. y
-1
-2
3 X
X+ 2y = 1
Answers to the Exercises 495
496 Foundation Maths for Engineers
v 20
10
0
2. (a) 5/3 (d) 5/3
3. (a) y = 5/3 x (d) y = 5/3 X - 1/3
Exercise 1.5.1
1. (a) . 0 Ttme 0.5 Amount 0 7.5
(b) 50
140 ~ 30
g 20 E ~ 10
2
Time(min)
2 t
(b) 2 (e) 12/4 = 3 (b) y = 2x (e) y = 3x- 41
1.0 1.5 15 22.5
e
(c) 2/3 (f) 6/3 = 2 (c) y = 2/3 x + 7/3 (f) y = 2x- 1
2.0 2.5 3.0 30 37.5 45
2. Rate of filling = 6 gallons per 100 sec = 0.06 gaVsec
Exercise 1.5.2
1. (a) Gradient = -5.8 gal/min (b) The tank is emptying
2. (a) Town driving is AB and EF. Motorway driving is BC and DE. Usually less fuel consumption on a motorway
(b) CD is petrol refilling
Exercise 1.6.1
Straight line graphs through the origin for (1) and (5) Note (3) and (4) are straight line graphs not through the origin
Exercise I.6.2
Direct proportionality for (r, q) graph only
Exercise I. 6.3
1. Current = 17.3 amperes when voltage = 8 volts; voltage = 7.4 volts when current = 16 amperes
2. (a) and (c); V = A x D where A is the area of the base
Exercise 1. 6. 4
1. When volume is 250 cm3, the mass is 200 grams. Mass= k x volume. k = 0.8 is called the density.
2. Yes, direct proportionality is a good model. F = 0.41 N
Exercise I. 7.I
1. (a) W = 3 when L = 15 (b) W = 1.125 when L = 40 (c) L = 19.6 when W = 2.3
2. If an inverse proportionality law is appropriate then the product of resistance and current is the same for each pair of data. It is a reasonable model in this case.
5 current = ---
resistance
3. (a) 33j% decrease (b) 100% increase (c) 16~% decrease (d) 25o/o increase
Exercise I.8.I
1. (a) d = 176.4 m (b) d = 11.03 m. When tis multiplied by k, dis multiplied by /2-.
2. P = cu3. Multiply u by 2 ~multiply P by 8. Multiply u by k ~ multiply P by ~. P is increased by 137%.
Exercise 1.8.2
1. p = kT/V
2.P=cv~
Exercise 1. 9.1
1. (a) R = 0.17T + 44.8 (b) (i) R = 48.2 ohms (ii) T = -263.5 °C
Answers to the Exercises 497
498 Foundation Maths for Engineers
2. I= 0.01T + 7.2 (a) (i) 7.45 em (ii) 7.75 em (iii) 7.95 em (b) (i) at 0 °C, I= 7.2 em
(ii) at 200 °C, I = 9.2 em (iii) when l = 14.8 em, T = 760 oc
Exercise 1.9.2
1. In Exercise 1, extrapolation is being used. In Exercise 2(a), interpolation is being used. In Exercise 2(b), extrapolation is being used.
Objective Test 1
1. Gradient = 3.1, intercept = -4.2, x = 3.1t - 4.2
2. Gradient (i) 2
(ii) 3 (iii) -4 (iv) -0.5
v y=2x+5
3. Q,R,A,D
4. (a) T vs x2
(c) W vs 1/P 5. p 2.4
P 2.78 x to-5
P = 8.6 X 104p
6. c 5 1000 32
y-intercept 5
-4 8 1.5
3.1 3.59 x w-5
R 0. 2 0.001 0.03125 C = 1/R
7. V = c~~
x-intercept -2.5
1.33 2 3
(b) p vs ljV (d) Tvs VL
4.33 5.01 x w-5
8. (a)
E .c:: 2 5 c:
"' 1;; 'ii a: 20
100 200 300
Temperature (°C)
R = 0.21T + 31.1 (b) 0.21 ohm/°C (c) (i) 52.1 ohm (ii) 115.1 ohm (d) -148 oc (e) c(i) because it uses interpolation.
CHAPTER 2
Exercise 2 .1.1
1. Quadratics Coefficients
a= b=
2x2 + 3x + 1 2 3 3x2 - 5x- 3 3 -5 7 + 4x + x2 1 4 -2x2 + 5 -2 0 -9x2 + x -9 1 -x2 - 3x + 4 -1 -3 4 - 20t + 9.8t 2 9.8 -20 1 + v + 0.7v2 0.7 1 u- 3u2 -3 1
Answers to the Exercises 499
c=
1 -3
7 5 0 4 4 1 0
500 Foundation Maths for Engineers
Exercise 2.2.1
y = 2x2 + 3x + 1 y
-4 y =-x2 - 3x +4
y
-1
Exercise 2.2.2
1. (a) -L -1 (c) -4, 1 (e) -1
2. (a) 0.85, -2.35 (c) -1, -2
1 X
y
2 X
v
y = -2x2 + 5
-4 4 X
v
y = 3x2 - 5x- 3
-2
y
-4 -2 2
(b) -1.6, 1.6 (d) 2.1, -0.5 (f) no roots (b) -1.4, 1.4 {d) -2, 1
4 X
X
3. (i) 2 m (ii) 2.04 s (iii) 4.18 s
Exercise 2.3.1
1. (a) x2 + 4x + 3 (c) x2 + 2x + 1 (e) 4x2 - 12x + 9 (g) x2 - 2x - 35 (i) x2 - u2
(k) 6x2 - 12x
(b) x2 - 3x + 2 (d) 6x2 + x- 2 (f) 2x2 + 7x - 4 (h) x2 - (u - v)x - uv U) r + 2x
Answers to the Exercises 501
Exercise 2.3.2
1. (a) x2 - 2x + 1 (b) x2 + 8x + 16 (c) 4x2 - 12x + 9 (d) x2 - 1 (e) x2 - 16 (f) 4x2 - 9
Exercise 2.4.1
1. (a) (x + 4)(x + 1) (b) (x- 4)(x + 1) (c) (x + 4)(x- 3) (d) (x + 5)(x + 2) (e) (2x + 5)(x + 1) (f) (3x - 1)(3x + 1) (g) (x + 3)2 (h) (x - 4)2
(i) (x - u)(x + u) (j) (2x + u)2
(k) x(x + 4) (l) x(3x - 10)
Exercise 2.5.1
l.(a)-1,-4 (b) -1, 4 (c) -4, 3 (d) -2, -5 (e) -2.5, -1 (t) L -~ (g) -3, -3 (h) 4, 4 (i) u, -u (j) -u/2, -u/2 (k) 0, -4 (I) 0, 10/3
Exercise 2.6.1
1. (i) (a) (x + 3)2 - 9 (b) (x + 5)2 - 25 (b) (x + 5/2)2 - 25/4 (d) (x + 7/2)2 - 49/4
2. (a) -4, -2 (b) -1, -9 -5 V21 -7 V61
(c)-±- (d)-±-2 2 2 2
Exercise 2.6.2
1. (a) 2(x + 2)2 - 8 ( 7r 49 (b) 3 X+- --6 12
(c) 4(x + %r- 12 ( 5r 17 (d) 2 X- 4 - g
3 5 V17 2. (a) x = -- ± Y3 (b) X=-±-
2 4 4
Exercise 2.6.3
1. (a) -4, -2 (b) -1, -9 5 V21
(c) --±-2 2
7 V61 (d)--±-
2 2
-1 ± V13 -1 ± V33 2. (a) (b)
2 4
502 Foundation Maths for Engineers
(c) L 1
(e) ± \15
Exercise 2.6.4
(d) -2 -5 ± \137
(f) 2
1. (a) 40- two roots (b) -8- no roots (c) 24- two roots (d) -16- no roots (e) 16- two roots (f) 49- two roots
2. K = ± V12 gives one repeated root K < -V12 or K > Vl2 gives two roots
3. (i) 1.58 m or S = 8.42 m (ii) 2 m or 8 m zero bending moment
(i) S = 0 m and 10 m 4. T = 307.5 oc 5. (a) w2 - 3w - 4 = 0
(b) 600w2 + 3200w - 1 = 0
Exercise 2. 7.1
(ii) S = 0 m and 10 m
w = 4 (must be +ve) w = 0.00031
1. ---------------------------Polynomial
4x5 + 3x2 + 2x + 1 9x7 + 8x6 - 4x3 + 2x ~- 3t2 + 4t + 1 u4 + 3u3 - 2u2 + u + 7 0.1x2 + 1.2x - 3.7 3.lx11 + 4x7
Degree
5 7 3 4 2
11
Exercise 2. 7.2
1. v V = x3 + 2x2 + 2x - 1
Exercise 2. 7.3
1. -1, -0.5, 0.3, 2 2. -0.33, 0.33, 1.50
Exercise 2.8.1
1. 2 2. 3.732
Exercise 2. 8.3
1. (a), (c) are no good near x = 3; (d) is quickest 2. (a) 0.38, 2.62
(b) 1.21 (c) 0.43
Exercise 2.9.1
1. 1. 2.18 s 2. 243.7 k
Answers to the Exercises 503
504 Foundation Maths for Engineers
3. 1612 K 2(M + m)g
4. 10 + --'------'-"'-k
5. V = 0 when T = 0 or T = 571.4 °C Vis a maximum when T = 285.7°C
6. (a) i = 1 or i = 4 (b) i = 0.58 or i = 1.56 7. R = 5.73 ohms orR= 39.27 ohms
r = 39.27 ohms orr= 5.73 ohms 8. x = 0.6 m or x = 1.639 m (to three decimal places) 9. 0, 3, 6, 10
Objective Test 2
1. (a) 2 (c) 1
2. (b), (d), (e)
(b) 8 (d) 3
3. (a) (x - 4)(x + 4); x = -4 or x = 4 {b) (x - 2)(x - 1); x = 1 or x = 2 (c) (3x- 1)(x + 2);x = -2orx = 1/3
4. x = 1.4 or x = 3.6
y
X
5. (a) R = -0.573 orR = 0.873 (to three decimal places) (b) x = -2.679 or x = 1.679 (to three decimal places)
6. (c), (a), (b)
3 X
-8
7. x = -1.180,x = 2.000
CHAPTER 3
Exercise 3.1.1
Exercise 3.1.2
1. r = G:Y/3 Exercise 3.1.3
1. f = 0.316R- 1/4
Exercise 3.2.1
1. ----------------------Number Base Index
7 21 a 2 a 5
3 13 4 n m 7
Answers to the Exercises 505
506 Foundation Maths for Engineers
Exercise 3.2.2
1. (a) 29 (b) 35 (c) a6 (d) x5
Exercise 3.2.3
1. (a) x7 (b) x 12 (e) 3k (f) x6
(i) aBb12 2. (a) x5 + a7
(c) -m2 - 5m3
3. (a) a5
(c) en+m-p
4. (a) 1 (c) 1
Exercise 3.2.4
1. (a) 1/4 (d) 1/27
2. (a) a-5
(d) p2 (g) e3x + e-x
(j) a3x-2 y-1
Exercise 3.2.5
1. (a) x1/2 (d) x5/2
1. (a) 2 (b) 8 (e) 32 (f) 512 (i) i U) 1
Exercise 3.2. 7
1. (a) k = 4 (d) a= 2 (g) a = 2/3 (j) a = -5/2
(b) 1/16 (e) 1/4 (b) x-3
(e) 6 (h) 9
(d) a2
(h) x15
(b) 6x5 - 10x11
(d) a3b + a2b2 - ab3
(b) 216x (d) 4a2bkt5
(b) 2 (d) 24
(c) 1/25
(c) m-2
(f) ab-1
(k) ~c2a2b-2 (i) 3x-1 y2 (I) m-3p x3n
(b) x3/2 (c) x1/2 (e) x1/2 (f) x- 1
(c) 3 (d) 2 (g) 100 000 (h) 4x3
(k) 2 (l) 10 000
(b) k = 2 (c) r = 5/3 (e) x = 0 (f) X= 3 (h) X= 1/2 (i) a = 4 (k) X= 3/2 (I) X = 0
Answers to the Exercises 507
Exercise 3.3.1
Physical Variables Rule Domain Range
Spring-mass oscillator
T, m T = 1.13m112 O<m<co O<T<co
Radiation heat E, T E = K(f4- To4) To~ T <co loss rate
Newton's Law F, r GMm O<r<co of gravitation F=--
r2
Exercise 3.3.2
1. (i) F(1) = 1 F(3) = 79.601 F(0.61) = 0.997 (ii) F(3.1) = 19.747 F(O) = 0
Exercise 3.3.3
1. g[f(x)] = 3x - 3 f[g(t)] = 3(t - 3) f[f(x)] = 9x g[g(t)] = t - 6
2. f[g(x)] = (x - 2)3
g[h(x)] = vx-::2 f{g[h(x)]} = (vx-::2)3
3. (a) Range of fis 0 < x < co; range of g is -co < x < co (b) f[g(x)] = v'(X=4") domain [4, co) range [0, co) (c) g[f(x)] = Vx- 4 domain [0, co) range [-4, co)
Exercise 3.3.4
(X- 4) 1. r 1 < x) = ...:..____:_
3
2. r 1(x) = (x + 3)113 - 1
Exercise 3.3.5
1. (a) x = 2.5 (c) no asymptotes
(b) X= -15/7 (d) t = -2, t = 2
O~E<co
O<F<co
508 Foundation Maths for Engineers
Exercise 3.3.6
X
y
X
Exercise 3.4.1
l y LL I
_j!, 7 I
I I I I I I
: (x=-!f)
y
1. ----------------------------------Function
Exercise 3.4.2
Rate of change
t = 1
approx 3.3 approx 2.3
t = 2
approx 9.9 approx 5.7
X
l
1. rate of change (i) when t = 1 is approx - 0.3 and (ii) when t = 3 is approx - 0.02
Exercise 3.4.3
1. n
1 1.5 2 3 4 5 10 100 1000 10000
Exercise 3.4.4
1. (a) 1.0000 (d) 5.4739 (g) 2.7183
(1 + 1/n)n
2 2.151657 2.25 2.370370 2.441406 2.488320 2.593743 2.704814 2.716924 2.718146
(b) 0.1353 (e) 1.3634 (h) 1.6487
3. It is not a reflection in any line! 4. 0.567
Exercise 3.5.1
1. (a) 4 (e) 1
2. (a) x = log3 7 (d) X= loge 4.1
Exercise 3.5.2
1. (a) 1.3979 (d) 3.0000 (g) 1.0000 U) 0.0000
3. (a) 0.4314 (d) -1.0459 (g) 4.4817
Exercise 3.5.3
1. 60 dB
(b) -2 (c) 1 (f) -2 (g) 2
(b) x = log6 4.1 (e) x = log2 8.3
(b) 1.0000 (e) 3.2189 (h) 1.9879 (k) 0.0000 (b) 1.4183 (e) 1.0492 (h) 37.9038
2. 0.100 wm-2 to three decimal places
(c) 20.0855 (f) 0.6570
(d) 3 (h) 6
(c) x = log10 12.2 (f) x = log5 7.6
(c) 0.8633 (f) 2.3026 (i) 0.3222 (I) 0.6931 (c) 0.6534 (f) 1584.8932 (i) 6.3246
Answers to the Exercises 509
510 Foundation Maths for Engineers
Exercise 3.5.4
1. T = 500e -o.41
2. t = 0.0805 seconds 3. t = 22.65 minutes 4. p 2 = 348.51 pascals 5. (a) 86071, 74082, 47237, 22313
(b) h = 4.62 km (c) h = 15.35 km
Exercise 3.5.5
1. (a) 2 log p + 3 log v (b) In p - In v (c) logs 6 + logs p + logs(a + b) (d) In 0.21 + In t- 1 (e) log s + log t - 1/2 log 3 (f) In 0.1 + 2 In v
2. (a) 1 (d) In (u3/v2)
(f) 0
(b) In 3 (e) Iog(xy2jp3)
(5wv) (c) log --;_;-
3. (a) x = 2.7381 (c) x = 0.5438
(b) X = -0.5217
Exercise 3.6.1
1. k = 0.0133 s- 1
2. T = 10.60 h 3. (a) x = 0.1652 min- 1 (b) 4.20 min 4. A,D,E 5. (a) 7 (b) 1/27 = 0.0078 (c) 0.9999 (almost all of it!)
Exercise 3. 7.1
1. (a) y = 3.4 x2·7
(b) v = 1.7 u-1.3 3. 1-L = 47.2 T-2·06
4. C = 0.12 x-2
Exercise 3. 7.2
3. H = 16.7 M 0·92
Exercise 3.8.1
1. v = 13.2 e-0-11
2. Graph of ln(k) against 1/T. k = 5.1 x 1012 x e-30300/T
Objective Test 3
1. (a) l/x2 1
(b)-ab4
1 (c)-
2xy2
2. Domain [3, oo], range [0, oo] 3. r 1(x) = j ln(x), domain [1, 2.117], range [0, 0.25]
(1 - x) g- 1(x) = , domain [0, 1], range [0, 0.25]
4
f[g(x)] = e3(1-4x)
4. (a) X= 0.4720 (b) X= 0 (c) X= 20.09 (d) X= 626.48 (e) X= 7.5546 (f) X= 2.1133
5. Half-life = 5599 yr, age = 3480 yr 6. y = 3 e-4x, s = 4.2 tl. 7
CHAPTER 4
Exercise 4.2.1
1. (a) 140° (b) 290° (c) 50° (d) 233° (e) 300° 2. (a) -160° (b) -161° (c) -22° (d) -45° (e) -80°
Exercise 4.3.1
2. 0.5, -0.8660; -0.5, -0.8660; -0.5, 0.8660; -0.5, 0.8660 3. 0, -1; -1, 0; 0, 1
Exercise 4.5.1
1. (b) 57.3, 573.0, 5729.6; -5729.6, -573.0, -57.3
Exercise 4.6.1
4. -0.342 5. 0.458 6. -1.192 7. -0.7 8. -0.1 9. 0.39
Exercise 4. 7.1
1. (a) ±98.2° (b) 7.2°, 172.8° (c) ±76.7° (d) -5.2°, -174.8° (e) -30°, -150° (f) ±90°
2. (a) 46°48', 133°12' (b) ±66°44' (c) -23°35', -156°25' (d) ±112°1'
Exercise 4.8.1
1. (a) 14.SO + 360°n; 165.SO + 360°n (b) 42° + 180°n (c) ±131.8° + 360°n (d) ±99.6° + 360°n (e) -41.8° + 360°n; 221.8° + 360°n (f) 45° + 180°n
Answers to the Exercises 511
512 Foundation Maths for Engineers
Exercise 4.9.1
3. 360° 4. 180° 5. 180°, 480°, 5
Exercise 4.9.2
1. 2, 4; 360°, 180° 2. 2, 1; 360°, 720°; 1, 0.5 3. 24°, 66°, 204°, 246° 4. 240°, 3/2
5. (a) 72° 5 (b) 1440° 0.25 (c) 600° 3/5 (d) 360/k k (e) 360/k k
Exercise 4.9.3
1. ------------------------------------------------
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Amplitude Max Min y = 0 at
1 1 -1 at -270°, 90° at -90°, 270°
2 2 -2 at -270°, 90° at -90°, 270°
0.5 0.5 -0.5
1
3
I 4
00
at -270°, 90° at -90°, 270°
1 -1 at 0°, ±360° at ±180°
3 -3 at 0°, ±360° at ±180° I I 4 4 at 0°, ±360° at ±180°
nla nla
2. (a) L 360° (b) 5, 360° 3. (a) 5, 360° (b) 10, 180° (c) 7, 480° 4. (a) 2, 3, 120° (b) 4, 2, 180°
(d) 0.73, 0.21, 1714°
Exercise 4. 9.4
±90°, ±270°
(c) oo, 180° (d) 1, 90°
(c) 4.3, L 480°
1. Shift 10° to the left. Period 360°, amplitude 1 2. Shift 40° to the right. Period 360°, amplitude 1. sin(6 + 50°) 3. 0°, 180°, 360°; 155°, 335°; 65°, 245°
4. tan 6: asymptotes 6 = ±90°; zero at 6 = 0°, ±180° tan(6 + Z0°): asymptotes 6 = -110°, 70°; zero at 6 = -zoo, 160°
5. (a) Z40°, Z, 30°; y = Z sinGe + 30°) (b) 120°, 1.7, 180°; y = 1.7 sin(3e + 180°)
Exercise 4.10.1
1. (a) 73.4°, 106.6°, 253.4°, 286.6° (b) 53.7°, 126.3°, 233.7°, 306.3° (c) 35.3°, 144.7°, Z15.3°, 3Z4.7° (d) 65.9°, 114.1°, Z45.9°, 294.1° (e) no solutions (f) 40.9°, 139.1°, Z20.9°, 319.1°
Z. (a) 45°, 135°, ZZ5°, 315° (b) 60°' 120°' 240°' 300° (c) 0°, 180°, 360° (d) 60°' 120°' 240°' 300°
3. (a) ±30° + 1800n (c) ±53.1° + 180°n (e) ±54.r + 180°n (g) ±50.8° + 180°n (i) ±62.7° + 180°n
Exercise 4.10.2
1. (a) Z4.3° + 180°n, 65.7° + 180°n (b) Z47.4° + 360°n (c) ±46.Z0 + l20°n
Z. (a) Z9.Z0 , Z40.8° (c) 45°, Z25°
3. (a) -104.9, 1Z6.9 (c) -40.0°, 80.0°
Exercise 4.11.1
(b) ±48.Z0 + 180°n (d) ±54.7° + 180°n (f) ±21.SO + 180°n (h) 45° + 90°n
(b) no solutions
(b) -159.0°,Zl.0° (d) -133.9°, 46.1°
1. (a) 7.2 (b) 96.4° (c) 81.9° (d) 130.9° (e) -Z3.6° (f) 34.3°
2. (a) 84°11', 264°11' (b) 116°34', 243~6' (c) 142°44', 32Z0 44' (d) 35°16', 114°44' (e) 211°5', 328°55' (f) 66~5', 293°35'
3. (a) ±48.2° {b) -154.2°, -Z5.8° (c) -36.9°, 143.1° {d) ±131.8° (e) 16.6°, 163.4° (f) -135.0°, 45.0°
4. (a) 360°; asymptotes at x = 90° and 270° (b) 360°; asymptotes at x = 0°, 180° and 360° (c) 180°; tan x has asymptotes at x = 90°, 270° and cot x at
X = 0°, 180°, 360°
Answers to the Exercises 513
514 Foundation Maths for Engineers
Exercise 4.12.1
1. (a) 420° (b) -30° (c) 225° (d) 540° 5 5 1T 5
2. (a) - 1T (b) - 1T (c) -- (d) - 1T 12 3 6 2
3. Period Amplitude Zero at
2 1T 21T 41T 51T (a) -1T 2 0,3':3'1T':3':3'21T 3
1T 31T (b) 21T 0.5
2' 2
1T 31T (c) 1T 5 0, 2' 1T, 2' 21T
4. (a) 31T/2 (d) 31T/4, 71T/4
(b) 1T/3, 51T/3 (e) 1T/3, 41T/3
5. ------------------Period Amplitude
21T (a)
3 1
(b) 1T 10
81T (c)
3 0.5
(d) 31T Y2
21T (e)
k 1
21T (f)
k a
(g) 1 b
2 (h) 1
n
(c) 1T/3, 21T/3
Exercise 4.13.1
1. Period (seconds) Frequency (hertz)
1 (a)
1T
(b) 2 O.S
211' k (c)
k 211'
2 k (d) -
k 2
2. 4 em, 1Hz 3. a = 30 mm, w = 411' Hz 4. i = 7S sin(1201Tt) rnA 7. (c) (e) are true 8. Amplitude = so, period = 3 seconds, phase angle= 0.7Sc,
e = s cos c; t) e = so when t = 3n seconds, n = 0, 1, 2, ...
e = 2.s cos ( 4; t)
Objective Test 4
1. 140° 2. -12.7° + 180°n, 102.7° + 180°n 3. 0.0717, l.SO, 2.17, 3.S9, 4.26, 5.69 4. 50.2° + 180°n 5. 1080°
811' 6. 5'2 7. Translate 30° to the right
n1T 8. X=±-
2
s 9. -Hz
211'
Answers to the Exercises 515
516 Foundation Maths for Engineers
CHAPTER 5
Exercise 5.2.1
cos e 1. (a)-.
sm e
(d) sine cos e
1 (b)-.-
sm e
(e) cos e
1 (c)--
cos2 9
1 (f) -sin-e -co-s -e
sine (g)-
cos e (h) sin2 e - cos2 e
Exercise 5.2.2
1. (a) 77/85 (d) 84/85
(b) 13/85 (e) -77/36
(A + B) is in quadrant II (A - B) is in quadrant I
(c) -36/85 (f) 13/84
2. (a) 0.8912 (d) 0.8820
(b) 0.4712 (e) -1.9652
(c) -0.4535 (f) 0.5343
(A + B) is in quadrant II (A - B) is in quadrant I
Exercise 5.2.4
2. (a) 5 sin(x + 53.1°) (c) V2 sin(x- 45°) (e) v106 sin(x + 150.9°)
Exercise 5.2.5
1. (a) 14.SO, 90°, 165.SO, 270° (c) 90°, 180°, 270° (e) 53.8°, 159.9°, 233.8°, 339.9° (g) 0°, 360°, 126.9°
(b) 13 sin(x + 22.6°) (d) Vl3 sin(x + 146.3°) (f) v666 sin(x + 54.SO)
(b) 68.SO, 291.SO (d) 0°, 45°, 180°, 225°, 360° (f) 96.8°, 263.2°
2. (a) 103.3°, 330.SO (b) 157.4° (c) 0°' 30°' 120°' 150°' 240°' 270°' 360° (d) 39.0°, 162.8°, 219.0°, 342.8°
Exercise 5.3.1
1. y
X
Exercise 5.3.2
1. (a) f(x) = 30° or 7r/6 (b) f(x) = -30° or -7r/6 (c) f(x) = 90° or 7r/2
X
g(x) = 60° or 7rl3 g(x = 120° or 27r/3 g(x) = oo or 0
(d) f(x) = 45° or 7r/4 (e) f(x) = -38.3° or -0.67 (f) f(x) = -71.8° or -1.25 (g) no function values
g(x) = 45° or 7r/4 g(x) = 128.3° or 2.24 g(x) = 161.8° or 2.82
(h) f(x) = 11° or 0.19
2. (a) 1.7321 (c) -0.4364 (e) 0.2316
Exercise 5.4.1
g(x) = 79° or 1.38
(b) 0.7141 (d) 0.8660 (f) no value
1. 2a sin(SOOt) cos(St), period 27r/5, a is amplitude of original waves 2. 2a sin 2ft cos ft 3. 2a sin(wt + 'P/2) cos('P/2)
Period is same as original wave. Amplitude is 2a cos('fJ/2) and phase 'fJ/2. (a) 'fJ = 0 : wave is twice original amplitude. (b) <p = 7r/2: wave is amplitude Y2a, and 7r/4 out of phase with
original wave. (c) <p = 7r : two waves destroy each other.
Exercise 5.4.2
1. x =A sin wt 5. P = E2 + J2(R2 + X 2) + 2EJ VR2 + X2 sin(2t + a)
a = arctan(R/X) where
Answers to the Exercises 517
518 Foundation Maths for Engineers
6. x = 5.63 sin(4t + 0.99), amplitude = 5.63 em and period = 1.57 s. t = 0.40 s.
7. 50 sin(51Tt + 0.64), amplitude =50, period = 0.4, phase= 0.64, t = 0.059.
8. 45° 9. y = -ix + 2
Exercise 5.5.1
1. (a) C = 75°, b = 4.90, c = 6.69 (b) c = 45°, b = 2.02, c = 3.39 (c) A = 69.9°, b = 11.90, c = 6.36 (d) B = 42.1°, C = 82.9°, c = 9.22 (e) C = 22.0°, A = 117.0°, a = 0.29 (f) C = 19.4°, B = 115.6°, b = 20.40 (g) A = 48.2°, B = 15.8°, b = 1.24 (h) B = 45.3°, C = 74.7°, c = 293
2. F2 = 13.7 newtons, angle = 42.6° 3. 104.6 metres 4. 036.9° 5. 18.7 metres.
Exercise 5.6.1
1. (a) c = 6.29, B = 67.1°, A = 37.9° (b) c = 3.39, B = 107.7°, A = 29.2° (c) c = 8.58, B = 10.2°, A = 42.8° (d) b = 337, A = 30.1°, C = 39.9° (e) C = 116°, A = 22.7°, B = 41.3° (f) C = 21.3°, A = 4.8°, B = 153.9° (g) a= 17.7, B = 40.4°, C = 66.6° (h) b = 13.33, A = 32°, B = 43o
2. 11.7 newtons, angle = 24.3° 3. Speed = 1119.5 knots, bearing = 267.1° 4. Distance = 62.6 miles, bearing = 078.2°
Objective Test 5
1. e = 'TT/3, 2.3 or e = 60°, 131.8°
b cos a + a sin 13 . a cos 13 - b sin a 2. cos x = , sm x =
cos( a - 13) cos( a - 13)
3. x + y = 6 sin 20t cos 5t
(x + y) ~ 6 sin (20t) cos (5r)
5. 5 sin(2x + 36.9°); x = 1S, 51.7° 6. 29.6°, 87.4°, 6.3; 3.8, 45.2°, 94.8°
CHAPTER 6
Exercise 6.1.1
1. 1/10, 1/100, 1/1000 3. 2.1, 2.01, 2.001 5. 3/4, 3/16, 3/64 7. 1' -1/10, 1/100 9. 3, 5, 7
11. Gr 13. Gr-1 15. 3(-1t-l
2. 1, 1/10, 1/100 4. 4, 3.1, 3.01 6. -1, 1, -1 8. 4, 2.9, 3.01
10. 2!, 2, 1~
( 1)n-1 12. -
4
14. 2( -1)n
16. c~r or (0.1Y
17. 5 + c~r 18. 1 _ c~r 19. £6650, £4655, £3258.50; £9500(0.7t
Answers to the Exercises 519
520 Foundation Maths for Engineers
Exercise 6.1.2
1. Gr-1. 0
3. (-l)n-l, no limit
1 n 5. 2--- nolimit
2 2'
2. 3 + Gr· 3
4. 5n, no limit
( 1 )n-1
6. 10 + 10 , 10
7. 0.8nCinit where Cinit = initial charge
( 1 )n-3
8. V2i, V 2 I, the squares shrink to a point
Exercise 6.1.3
1. ± (J..)n-1 n=l 10
5
3. L (2n- 1) n=l
31
5. ~ xn-l
n=l
Exercise 6.1. 4
1. 5050 4. 15 150
Exercise 6.2.1
1. 29 5. 10
Exercise 6.2.2
1. 5050
2. 2870 5. 2185
2. 25.25 6. 101
2. 318.5 4. 860, 1890, 1030
Exercise 6.3.1
1. 1.2, 13.437 (three decimal places
3. 15th term 5. £8192
2. tGr 10
4. L (-lt-12n n=l
3. -7 7. 51
3. 18 496 6. 180 125
4. 15, -2
3. 7.5 5. 825
2. -0.8, 13.422 (three decimal places)
4. 7 seconds 6. 21.5%
Exercise 6.3.2
1. 453.320 (three decimal places)
3. 32.675 (three decimal places)
5. 26/21, 4
Exercise 6.4.1
5 1.-
9
18 4. 5-
99
Exercise 6.4.2
1. 75 3. Does not exist 5. Does not exist
1 10
37 2.-
99
17 5. 5-
90
7. 3 - m, - m from A 3 17
2. 5.601 (three decimal places)
4. 1/4
2. 5 4. -3j 6. 8
417 3.-
999
442 6. 3-
495
8. 20 units, (8, 4)
25 9. 1.316 m (three decimal place),- (1 - 0.62n), n = 11
19
10. 60'1T em
Exercise 6.5.1
1. q = x2 - x - 1; r = 2 3. q = 6x2 - 2x + 5; r = 8 5. q = - t2 - t - 1; r = 1
Exercise 6.6.1
1. 5 2. 8 5. -48 6. Yes 9. Yes 10. No
12. (t + 1)(t + 2)(t + 6)
Exercise 6.6.2
2. q = 2x2 + x - 3; r = 0 4. q = 3x - 4; r = 20x - 21 6. q = !v - ~; r = 2!
3. 0 4. -1 7. Yes 8. No
11. (x- 2)(x + 3)(x- 4)
1. 2~ 2. 2 3. -1i 4. No 5. Yes 6. Yes 7. (x - 2)(2x + 1)2
8. (x + l)(x - 3)(2x - 1) 9. (t + 1)(t - 2)(3! - 2)(! + 4) 10. (y - l)(y - 2)(2y + 1)(3y - 2)
Answers to the Exercises 521
522 Foundation Maths for Engineers
Exercise 6. 7.1
l.x2 +9 3. (x - 1)(x2 + x + 1) 5. (x - 3)(x2 + 2) 7. (y + 3)(2y2 + y + 3)
Exercise 6.8.1
2. (x + 3)(x - 3) 4. (x + 1)(x2 - x + 1) 6. (1 + 1)(1- 1)2(t + 2) 8. (3z - 1)(z2 + 2z + 3)
1. Improper 4. Proper
2. Improper 5. Proper
3. Improper 6. Improper
2 7. 4+-
x- 1
3 9. s + 2 + -
s- 1
Exercise 6.8.2
1 1 1. --+-
x+1 x-1
4 3 3.-----
1-1 1+2
1 1 5.---
2(x - 1) 2(x + 1)
Exercise 6.8.3
1 1 1 1. --+------
1 - 3 I + 2 (1 + 2i 2 5 1
3. -+-+-X x2 x-1
3 1 1 1 5 ---+ ---
. x2 x (x - 1)2 x - 1
Exercise 6.8.4
X 4 1. --+-
x2+2 x+1
2 1 1- s 3. --+--+-
s + 1 s + 2 s2 + 1
1 4 3 5 ---+--.1 12 12 +1
8. 3 - (31- 3) 12 + 31 + 1
1- y 10. 2y- 1 + 2
1 + 2y- y
2 3 2.--+--
1-21 t+1
2 4 1 4.-----+-
x+1 x-1 x-2
1 1 2. 2+---
2(2x + 1) 2(2x + 3)
1 2 1 4.- +-+--
t3 t t + 1
3 1 + 2t 2----
. t t2 + 3
1 2v - 3 4. -+--
v v2 + 1
Exercise 6.8.5
3 1 1. 2v - 1 + - - --
v v + 1
1- X 3 3. X+--+-
x2 + 2 x
Exercise 6.8.6
1 l.---
1
6(x- 3) 6(x + 3)
3 1 3.--+--
x-2 x+2
1 1 1 5.-- +---
2x 3(x + 1) 6(x + 2)
2 t 7----
. t t 2 + 1
Exercise 6. 9.1
1 3 2. 2+------
t + 1 (t + 1)2
2 1 4. 5 +-----
x-2 x-1
1 2.---
1
2(v + 1) 2( v + 3)
2 1 4.-----
v + 3 2v + 1
2 3 6. 1--+-
t t- 1
1-2x 1 2 8. x 2 + 1 + (x + 1)2 - x + 1
1. x6 - 6x5y + 15x4y2 - 20x3y3 + l5x2l - 6xy5 + l 2. a7 + 7a6b + 21a5b2 + 35a4b3 + 35a3b4 + 21a2b5 + 7ab6 + b7
3. 243p5 + 405p4q + 270p3q2 + 90p2q3 + 15pq4 + q5
4. 81x4 - 216x3y + 216x2y2 - 96xy3 + 16/ 5. 1 - 5x2 + l0x4 - 10x6 + 5x8 - x10
6. 81 v4 - 54v3 + 27/2 v2 - 3/2 v + 1/16 7. 1 - 3/x + 3/x2 - 1/x3
8. t6 + 6t4 + 15t2 + 20 + 15/t2 + 6/t4 + 1/t6
Exercise 6.9.2
1. 24 4. 840 7. 11.10
2. 1 5. 30 240 8. 11.5
10. n(n - 1)(n - 2)
Exercise 6. 9. 3
1. 15 4. 12
Exercise 6.9.4
2. 56 5. 3
1. u3 + 6u2v + 12uv2 + 8v3
3 1 1 2. x4 - 2x3 + - x 2 - - x + -
2 2 16
3. 3 628 800 6. 9 9. n
3. 252 6. 21
Answers to the Exercises 523
524 Foundation Maths for Engineers
10 1 3. 32t10 + soP + sor4 + 40t + - + -
r2 ts
4. 11520s8r2 21
7. -p5 32
Exercise 6.10.1
1. 1 + 4x + 12x2 + 32x3; I x I < !
6. -48384v5
9. 490
2. 21;5 (1 + __!_ y - __!_ l + 2_ l) · I y I < 2 10 50 500 '
3. 32/5 (1 - _i_ t- _i_ t2 - ~ t3) • I t I < 3/2 15 75 3375 '
1 1 1 4. x112 -- x- 112 y -- x-312y2-- x 512l· I Y I < I xI
2 8 16 '
1 1 5. 10 +- x- -- x2• 10.149
20 8000 '
6. 3.936
1 x x 2 x3 7.- +--- +-
2 4 8 16
Objective Test 6
3(-1t 1. 1 2n-
3. 16, 5
1 5. -3-
32
X 1 7.--+-
x2+2 2x+3
t t2 10. 2----
12 288
2. 1
4. 1.92 mm
6. (x - 2)(x + 3)(2x - 1)
1 3 8. 2x+----
x 2x + 1
CHAPTER 7
Exercise 7.1.1
The complete list of average velocities (ms- 1) is
0.7, 2.1, 3.8, 5.7, 8.1, 11.3, 15.1, 20.1.
Exercise 7.1.2
1. Yes. We shall see that the instantaneous rate of change is obtained from the average rate of change as time steps decrease in size.
2. Average decay rates are correct to three ·decimal places.
0.118 0.104 0.092 0.081 0.071 0.063 0.056 0.049 0.043 0.038 0.034 0.030
-'~ "' i 0.12
> .. 0 .,
"0 ., "' ::: ., >
<( 0 120
Time Is)
Exercise 7.3.1
1. Instantaneous velocity is 7 ms- 1•
2. Instantaneous rate of change of current is -0.4 As- 1.
Exercise 7.3.2
2. Gradient of f(t) = t2 is 4; gradient of f(t) = t 5 is 80
Exercise 7.4.1
1. -2t
Exercise 7.6.1
3 5. - t112
2
1 9. -- u-5/4
4
2.
6.
10.
2. 9t2 - 8t 3. X+ 1
3 -4 - X 3. -t-2 4.
1.1 VO.l 7. -1.1v-2.1 8.
lx0 = 1
i cl/2
1 _ u-2/3 3
Answers to the Exercises 525
526 Foundation Maths for Engineers
Exercise 7.6.2
1. 4x3 - 3x2 + 8x - 8
5. 24t-4
4 7 7. - u-2/3 +- u-I/2
3 2
1 9. 6t--
4
Exercise 7. 7.1
1 2. -- x-112
2
1 4. - rl/2 + 3
2
6. -1.2v-2·2
2 8. -- t-1/3 + t-3/2
3
10. 27rt
3 1. - xl/2
2
1 2. -- x-3/2
2
1 3. 1- -x-1/2
2
7 4. 3-2
X
Exercise 7. 7.2
1. 6t
2 6. -- x-5/3
9
10. 0
Exercise 7.8.1
2. -2
7. 2
5. 2.1xl.l - 1.1x0·1
3. 0 2
4. 3 t
8. X+ 1 4
9. - x-7/3 9
1 1.-
6
1 2. -
9 (1 65) (3 59)
4" 3 ' 27 ' 5 ' 25
6. 12x - 12; x = 1 m 7. 1.832 sm-1
8. 250 Jsm-1 9. 6 WA - 1
11. t = 10 s 12. 3y = 17x - 21 13. (2, 6), ( -2, -6), y + 3x = ±12 14. y = x + 3; (0, 3) 15. y = 8x - 21
Exercise 7.9.1
1. -2x3(2 _ x4)-1/2 2. 2(4- x)-3
3. 3(2x + 1)(x2 + x + 1)2 4. 0.3x2(x3 - 1)-0·9
1 5. - (3r2 - 6t + 1) (f - 3rl + t - 1)-1/2
2
3 6. -- (1 + 3t)-l/Z
2
1 8. 2t - - (1 - t)-l/Z
2
2 10. -v-2 +- v(v2 - 2)-213
3
Exercise 7. 9.2
1. 94.2 cm2s- 1
2RI 3 ----
. (t + 1 )2
500 5.-2
1TW
7. 1 - (1 + t)-2
2. 0.00796 cms- 1
4. 0.0111 ms-1
-2 6. 3 ; -0.0741 ms-2, -0.000216 ms-2; -2.46 x 10-7 ms-2
(2s + 1)
Exercise 7./0./
1. -4; decreasing 3. 39; increasing
5. -1/Y2; decreasing
7. <-L -1) 9. (0, 1)
11. None
Exercise 7.10.2
1. ( -1, 2) minimum 3. None
Exercise 7.10.3
1. Max - -( 1 17) 2' 4
3. Max ( -3, -27D, min (3, 27!}
2. -1; decreasing 4. 0; stationary
6. G · 112)
8. (0, 1) 10. (0, 0) 12. (1, -3) and (-1, 5)
2. (0, 1) inflection 4. (1,2),(-1,2)minima
2. Min ( -2, -16), max (2, 16)
4. Min (0, 1) 5. Max ( -1, 3), min (0, 0), max (1, 3)
Answers to the Exercises 527
528 Foundation Maths for Engineers
Exercise 7.11.1
1. 2x(2x + 1)2(5x + 1)
3. - x(1 - x2) 112(1 + Sr)
44 5. 2
(10- 7x)
1 7. - (1 - t)- 112(1 - 6t)
2
1 - t2
9. 1 + 2 2 (1 + t)
1 2. - (x + 1)-If2(3x + 2) + 2x
2
2x2(x + 6) 4. 2
(4 + x)
2x(1 + x2) 6. 3(2 + 2
(1 + 2x)
1 8. - t(6 - t)-7/3(36 - 7t)
3
t112 [ 9 + 2t ] 10. 3t2 +-2 (3 + 2t)2
11. (-1, -!)minimum, (1, D maximum 12. (1, !) maximum
Exercise 7.12.1
1. 1.633 m from A, deflection of 2.2 mm 2. R1 = R2 =50 kfi; P = 0.1 W 3. 62.8 mpg at 51.8 mph 4. 37.5 m x 25m 5. h = 85.4 em, r = 39.8 em 6. One 1 m diameter; other zero diameter
Exercise 7.13.1
1. COS X
2. -sin x (i.e. the sine graph inverted)
Exercise 7.13.3
1. -cosec2 x 3. -cosec x cot x 5. ! sec2(!x) 7. 2 sin x cos x 9. 2x cos(x2)
11. -sin ex sin x 13. 2w cos wt, - 2w2 sin wt
2. sec x tan x 4. -5 sin 5x 6. 8.
10. 12.
-sin x + 2 cos x 6 tan x sec 2x -4 cos 2x sin 2x cos 2x
14. -2w cosec 2wt cot 2wt, 4w cosec 2wt (cot2 2wt + cosec2 2wt) 15. cos wt - wt sin wt, -w (2 sin wt + wt cos wt) 16. -2w sin(2wt + ex), -4w2 cos(2wt +ex) 17. 2w sin(wt- ex) cos(wt- ex) = w sin[2(wt - ex)],
2w2 cos[2(wt- ex)] 18. w cos 2wt, - 2w2 sin 2wt
a 1T 19. e =- +-
2 2
20. e =arctan v'2 (= 54.7°), V = 21Tz3/9v'3
Exercise 7.14.1
3. 1.00 4. 1.10
Exercise 7.14.2
1. -6e-6x 2. ~(ex - e-x) 3. -2xe-x2
4. e2x(l + 2i) 5. -el-x 6. xe-x(2- x) 7. e-21(cos t- 2 sin t) 8. ea1(a cos wt - w sin wt)
10. e-1[wcos(wt + a) - sin(wt + a)]
13. y =ex, ey + x = e2 + 1, A(O, 0), B(e2 + 1, 0), !e(e2 + 1) 14. (-1, -e), minimum 15. 5e-31 (2 cos 2t- 3 sin 2t), 5e-31(5 sin 2t- 12 cos 2t); 0.294 s
Exercise 7.14.3
1. ~In a
Exercise 7.15.1
1 1.
x
3 5.-
X
1 1 9. ---
t2
12. 2t In(2t) + t
15. 1
2 2.
X
1 6.-
2x
2. 2x In 2, 32x In 9
2at 10. 1 + aP
2 3.
X
1 7. 1 +
t
2 - In t2 13.--
(2
6 Int 16.
t
2 4.
X
1 8.--
a2 11.
t
1 + t
2t In t- t 14. (In t)z
18. (0, 0), minimum
Answers to the Exrecises 529
530 Foundation Maths for Engineers
Exercise 7.16.1
(1)
(3)
3 y=--2
(5)
(6)
y
y
---'r:-----~ .-IN/
II I '<
I I
y
(2)
(4) y
(2, 4)
I
:L:=x2-8 1 x-3 I I I I I I (4,8) I
I I IM Ill I'<
/ /
X
X
y = e• cos2x
X
17) y
X
(9) y
Exercise 7. I 7.1
1. 6 cos(2x)
3. 0
(8) y
(10)
I I I I~ I,: I'< I I
2. -l sec2 (2:. - ::) 2 4 2
4. (2x e-zx- 2x 2e-2x) sin(2x) + 2x2 e-zx cos(2x)
-2x2 sin(2x) - 2x cos(2x) 5. 4
X
6. 2 cos(2x) cos(3x) - 3 sin(2x) sin(3x)
2e3x 7. 3 e3x ln(2x + 1) + --
(2x + 1)
8. sec2(x) sin(2x) + 2 tan(x) cos(2x)
9. 12 sin(l - 4x) 10. 20 e41
11. -14 e-21 12. e21 + 2te21
X
X
13. 2t e12 14. 2e21 sin(4t) + 4e21 cos(4t)
15.-----e8r
ds 18. v == - = 2 + lOt
dt
2 16. -
t
4 17.---
(3 - 4t)
(a) t = 0, v = 2 (b) t == 2, v = 22 (c) t = 4, v = 42 19. dT/dt = -500 e-51
(a) t = 0, dT/dt = -500 (b) t = 1, d7/dt = -500 e- 5
20. dM/dt = 4.3(-2.1 e-2·11) = -9.03 e-2 11
Answers to the Exercises 531
532 Foundation Maths for Engineers
21. v = ds/dt = 0.21 cos(0.7t) a= dvjdt = -0.147 sin(0.7t) (a) t = 0, v = 0.21, a = 0 (b) t = 1, v = 0.21 cos(0.7) = 0.161,
a = -0.147 sin(0.7) = -0.095 22. (a) r(t) = 9 em
(b) r = 3 when t = 1 second (c) dr/dt = 9/t2 = 9 when t = 1 (orr= 3) (d) Largest value of r is 12 em [lim,_.oo r(t)]
23. Speed v = dh/dt = 21 - lOt. The table shows the results.
(a) t (s) v (ms-1)
1 11
2 1
3 -9
4 -19
(b) The stone comes to rest when v = 0, i.e. when t = 2.1 seconds. (i) Initially v is positive so that the stone is climbing for
t < 2.1. (ii) For times t > 2.1, the value of vis negative, so that the
stone is falling.
1 - t 2 9 24. 2 2 ; t = 1;- ; it approaches (0, 4) along the axis
(1 + t ) 2
5 1 25. t =- ; v = -- e-5/4 = -0.0358
2 8
26. -8.08 ms-2
27. (3, 1), X + 3y = 6 28. (a) 41 (b) 36 (c) y = 36x- 31 (d) X + 36y = 1478 29. (a) Pis a maximum when X= R
(b) p
X
30. (b) f(a)
31. (a) yv// 1
y=x+X
v (1, 2) /
/
(c)
32. (a) Vo =
(b)
I I I I~
I~ I'<
p
X
"'
Answers to the Exercises 533
(b) y
y = 1
I
"'1~+2 Ill y=--
-~~---x-6 _
X
(d) I y I
~ y = 1
I 3 X ,, -3 II I x-3 y=--'<I x+1
534 Foundation Maths for Engineers
Objective Test 7
1. 15.08, 15.08 (three decimal places)
1 3. - - x - 2x In x
X
5. y = 1
7. -0.081
CHAPTER 8
Exercise 8.1.1
2. -2.297
4. (1-p)-2,2(1-p)-3
6. 36191 mm3s-1
8. ( e-1/2, - ~ e-1)
1 10. -+cot x
X
s should settle down to 35.33 m, but there may be trouble with rounding errors
Exercise 8.1.2
1.3m 2.5jm,-2jm 3. v'12 """ 3.46 s
Exercise 8.3.3
1. ( q6 - p6)j6 5. ~
2. 20 3. 7.5 4. 2(2v'2 - 1)/3 7. 1.5125, 12j, 1~ 6. 12.4
8. -4, 4, 0, 8
Exercise 8.4.1
In each case c is an arbitrary constant.
1. X+ C
5. -cos x + c
Exercise 8.5.1
1. -cos t + e1 + c
1 2. - x3 + c
3
3 4. -x4 + c
16
1 3 6. - x3 + - x2 + c
3 2
u3 3 2. - + - u2 + Bu + c
3 2
3. -1/v + c 5. 2v'x + c 7. tan x + c
Exercise 8.6.1
1. 12.4
5 6.-
6
2 2.-
3
2 7. 26-
3
2 3. 3-
3
2 8. 25-
3
4. 2pl/2 + c or 2 V p + c 6. -e-x+ c 8. -cot x + c
1 4. 1-
8
11 9. 1-
15
1 5. 1-
3
19 10. 3-
24
2 1 11. 21-
3 12. 53.99 (two decimal places) 13. 3- 14. 12
3
1 1 2 15. 12-
3 16. Integral = - - area = -
6 ' 6
1 1 17. Integral = -1- area = 1-
3 ' 3
1 19. 4-
2
1 20. 1-
3
2 21. 10-
3
1 22. 1-
3
25. 2 + e-1 - e-3 = 2.318
Exercise 8. 7.1
1 1. - - cos 3x + c
3
1 3. - (2t - 1)312 + c
3
5. i sin ( 2x - ; ) + c
1 7. - (x2 + 2x - 1)6 + c
12
1 9. - (3 - 2v)-2 + c
4
3 11. - -(1- eY)413 + c
4
5 13. - (1 + 2v)l.2 + c
12
Exercise 8. 7.2
A is a positive arbitrary constant.
26.2 27.e - 1
2 2. - (x - 1)312 + c
3
4. -cos ( x + ; ) + c
1 2 6. -ex + c
2
1 8.- --+ c
1 + t
1 10. - (2t + 1f12 + c
7
5 12. - (1 + v)I.2 + c
6
Answers to the Exercises 535
536 Foundation Maths for Engineers
1. ln(Ax114) 2. ln(Ax2) 3. ln(Ax9)
7 4. - 2ln[A(1 - 2x)) 5. ln[A(3t + 2)113]
6. ln[A(3t - 2)1f3]
1 9. -ln[A(ax + b))
a
1 11. -ln[A(1 + t)]
3
1 7. -ln(Ax)
a
a 10. - ln[A(bx + c)]
b
2 12. - ln[A(4 + tl2)]
3
8. a ln(AX)
Note that in each case the constant of integration could be added on; i.e. in 1 the answer could have been written
ln(x114) + C or ~ ln(x) + C.
Exercise 8. 7.3
1. .!. 2. .!. ln (2.) 3 5 4
1 4. 3 (3v3 - 1) = 1.399
3. ~ ln (~)
5. ~ ln (~) 6. 9
1 7.-
4 8. -0.575 (three decimal places)
1 1 9 -----
. 4 2(1 + e2)
Exercise 8.8.1
1. ln(sin e) + c
4. -ln(1 + cos e) + c
6. ~ ln (I) 1
8. - ln(1 + 2x) + c 2
Exercise 8.8.2
1 1. - arctan(3x) + c
3
v3 10.-
2'7T
2 2. - ln(2 + ~2) + c
3
5. ln(V6)
1 3. - ln(sec 29) + c
2
2. ~arctan (~) + c
1 (3x) 3. 6 arctan 2 + c
5. arcsin x + c
1 (bx) 7. b arcsin -;; + c
1T 9.-
24
Exercise 8. 8.3
1. ln(cosec e - cot e) + c 2. -2(1 + tan e/2)- 1 + c
Exercise 8.8.4
1 1 1. - x - - sin 2x + c
2 4
1 3. - (x + sin x) + c
2
Exercise 8.9.1
1. X sin X + COS X + C
3. !x sin 2x + i cos 2x + c
2 5. - (x + 1)312 (3x - 2) + c
15
4. ~ arctan (bx) + c ab a
6. arcsin (~) + c
1T 8.-
6
1T 10.-
12
1T 1 2.---
8 12
1 1 4. -+-
16 811'
2. (x - 1)ex + c
1 2x 6. - (2 - 9x2) cos 3x + - sin 3x + c
27 9 xz xz
7. -(x2 + 2x + 2)e-x + c 8. -In x-- + c 2 4
Exercise 8.9.2
4 1.- (11\12- 4)
15
1 3. l5 (297 - 56\17)
5. 8(11'- 2) 7. 2 In 2 - 1
2 4.--
9
6. 8(5e2 - 1)
Answers to the Exercises 537
538 Foundation Maths for Engineers
Exercise 8. 9.3
1 1 1. 2 ex (sin X - COS x) + C 2. -e-x (sin x - cos x) + c
2
1 2 3. - e2x (cos 4x + 2 sin 4x) + c 4. - (e, - 2)
10 5
2 1 5. - - - (V3 + 2)e-,16
5 10
1 6. - (3V2e, - 4e,l2)
10
Exercise 8.10.1
In A and c are arbitrary constants.
[A(x + 1)3] 1. In 2 or 3 ln(x + 1) - 2 ln(x - 1) + c
(x- 1)
3 2. ln[A(x + 3)4(2x - 1)312] or 4 ln(x + 3) + -ln(2x - 1) + c
2
1 1 3. -ln[A(2x + 3)(2x - 1)] or -ln[(2x + 3)(2x - 1)] + c
4 4
[Ax\x- 1)]
4. In 2 or ln[x5(x - 1)] - 2 ln(x + 3) + c (x + 3)
2 5. - ln(3x + 1) + 3 arctan x + c
3
6. ln[(x + 3)2Yx2 + 1) - arctan x + c
1 or 2 ln(x + 3) +- - ln(x2 + 1) - arctan x + c
2
1 2 7. - -- + -ln(3x - 2) + c
X + 1 3
8. ln(2x + 3) +~arctan (~) + c
9. In(2.7) 10. In G~)
Exercise 8.11.1
1T 1.-
7
1T2 2.-
2
3 11. In 160 --
2
10161T 4.--
15
11" 5.-
2
9. 11"
Exercise 8.12.1
11" 6.-
2
12811" 10.--
7
2. (~ ~) 5, 7
11" 7.-
5
3. (~ ~) 2 , 8
5. (0.459, 0.402) to three decimal places
Exercise 8.13.1
1. 4
3. 3.1312
5. 1
1 7. - (e4 - 1)
8
2. 16.5
4. ! ln(x2 + 1) + c
1 1 6. - te3t - - e3t + c
3 9
8 . .!_ ln ( 2 + x) + c 2 2-x
1 1 9. - - Vl - 9x2 -- arcsin(3x) + c
9 3
1 10. --cos2x+c
4
14. In -- + c (X- 2) x+3
1 16. -sin 1rx + c
11"
19. (2 - x2) cos x + 2x sin x + c
11. 0.5 + ln(3/4)
13. In(r - 3) + c
15. In (%)
x2 sin2 x x sin x cos x (x) 20. 4 + - 4-- 2 + c 21. i arctan 2 + c
22. ! ln(t2 + 4) + c 23. ! ln [ G ~ ~) ] + c
24. - iJn(t2 - 4) + c 25. u +In u + c
Answers to the Exercises 539
540 Foundation Maths for Engineers
26. u - ln(u + 1) + c
2 28. t-- + c
t
30. ! ln(t2 + 2) + c
32. ! arcsin x + i xV1 - x2 + c
1 34. - -ln(5- 6t) + c
6
1 36. 3(5 - 6t)l/2
1 38. - u3 (3u2 + 5) + c
15
t2 27. 2 ln t + - + c
2
29. t- V2 arctan (~2) + c
2 33. - -(1- x)312 + c
3
1 35. + c
6(5 - 6t)
(u2 + 1)2 37. + c
4
1 39. - [ u(2u2 + 1) V u2 + 1 - u - ln V u2 + 1 ] + c
8
Objective Test 8
1. ? + c
2.4(1-~2) 3. 1
e- 1 4.--
2
6. ~arctan (k) + c
7. _!_ ln ( 8 + t) + c 16 8- t
1 1 8. - x +- sin(2'TTx) + c
2 4'TT
In each case c is an arbitrary constant.
CHAPTER 9
Exercise 9.2.1
1. y = 2x2e 3. y = 5- ze-x 5. X= 4(1 - t)
Exercise 9.3.1
y
I 3
I
/
/
-3
" \
\
3
I I I I
I I I I
I I I
/ / / / /
/ / / / /
"" " " " \ \ \ \ \
\ \ \ \
\ \ \
I -3
y
\ " /3
\ " - /
I I I I I
I I
/-3
3
2. y = ln(2x + 3) 4. y = arctan t + -rr/2
I
I
/ / / / / /
/ / / / / /
3 X
" " " " " " \ \ \ \ \ \
\ \ \
I I I I I
-3 X
/ - ' \ \ \
/ " \
Answers to the Exercises 541
y
\ \3 I
\ \ I I I
\ I I I
\ I I I \ \ I I I
I \ \ I I I
-31X
\ \ I I I I
I \ \ I I I I I \ \ \ I I
\ \ \ I I I
\ \ \ I I I
\ \-3 I
2
y
- - - - - -3
I I I I I I
I I I I
3 -3 X
I I I I I I I
- - - - - --3
4
542 Foundation Maths for Engineers
Exercise 9.4.1
In the following answers, A and Care arbitrary constants.
1. y = Ax3
3. y =COS X+ C 5. l =A e1
7. C - COS X = ! t2
1 9. -- = e 1 + C
X
11. y = 4x2 + 1
1 13. y = 1 - - sin 2wt
2w
'TT 15. arctan y = t2 + -
4
17. e2x = 2[2- e-1(1 + t)]
2 4(1 + t)2
19. 1 +X = 4 (1 - t)
Exercise 9.5.1
1. 0.711 m, 147 s
Exercise 9.6.1
1. 3.003
Objective Test 9
1. y=!sin2x+c
3. i = V(e12 + c)
5. 1.136
CHAPTER 10
Exercise 10.2.1
1. (a) 10 gram
2. 1.084
2. y2 - x2 =A 4. y =A ek1
6. ln y = t2 + 4t + C
8. e-x = C - ~ t 3
10. cot y = C - ! sin 2x
12. y = 3e-Zx
14. 3t2 + 2e-3Y = 2
16. x2 = arcsin(2t)
18. sin 2wy + 2 cos wy = 2
20. y sin y + cosy = ex
2. m = e-0.0127t
3. 1.096, 1.095
2. v = Ael.512
4. y = el/(x+l)
(b) 0.1, 10%; 0.01, 1 %; 0.00001, 0.001% (c) 127 < m < 147
2. 3.135 < m < 3.145
Exercise 10.2.2
(a) error I = 0.0015; 5.4975 < n < 5.5005 (b) error I = 0.0056; 23.8914 < n < 23.9026 (c) error I = 0.0090; 2.4099 < n < 2.4278 (d) error I = 0.0058; 6.8007 < n < 6.8123 (e) error I = 0.9 331.50 < n < 333.30 (f) error I = 0.0045; 2.3923 < n < 2.4013
Exercise 10.2.3
(a) E = 0.019 ; e132 = 3.743 ± 0.019; 4.0 to appropriate accuracy (b) E = 0.050 ; cos(l.5) = 0.0707 ± 0.0499; 0.0 (c) e = 0.00019; ln(2.634) = 0.9685 ± 0.00019; 0.97 (d) E = 17.28 ; e<2·1)2 = 82 ± 17; 100 (e) e = 0.08 ; 3.42e132 = 12.80 ± 0.08; 13
Exercise 10.3.1
1. For root near x = 3.4, method (d) only. For root near x = 0.6, methods (a) and (c) could be used. (c) would converge more quickly.
2. Use method (a); x = 0.567 to three decimal places.
( 1- X) 3. (a) Xn+l = sin- 1 T ; x = 0.338
(b) X = V1 + 2e xn · X = 1 253 n+l ' ·
1 + 2x2 - x3
(c) Xn+l = n n ; X= 0.430 3
Exercise 10.3.2
(a) X= 0.5858 (b) X= 0.5671 (c) X= 0.3376 (d) X= 1.2534 (e) x = 0.4302
Exercise 10.4.1
1. (a) 2.927 (b) 0.2438 (c) 0.6932 (d) 3.142 (e) 0.1054 2. 0.62 km 3. 35.8 ms- 1
4. e = 49.03 (simple average = 49.45)
Objective Test 10
1. e = 0.389; appropriate answer 63 2. For the root near 0.3, methods (a) and (c) cannot be used.
Quickest method is (d). For the root near 5, methods (b) and (d) cannot be used. Quickest method is (c). Roots are 4.9571 and 0.3429.
4. (a) -0.39 (b) 0.83
Answers to the Exercises 543
544 Foundation Maths for Engineers
CHAPTER 11
Exercise 11.1.1
force, velocity, displacement.
Exercise 11.1.2
1. N
Derby
Leicester
Scale 10mm = 10km
2. 16N
Stone
30 N Scale 2 mm= 1 N
3.
131 mph
Scale: 1 em =20 mph
N
••--•.,..2N Scale: 1 em= 1 N
(v)
(iii) Oxford 1-------
Scale: 1 em =2 N
F 19.6 N
(ii)
r Scale: 1 cm:oc10mph
Exercise 11.2.1
1. c = k, d = f, e = n 2. (a) e = -2a
(d) m = 2d (g) l = 1¥/
3. (i) = (vi), (ii) = (v)
Scale: 1 cm=20km
Portsmouth
(vii)
70 mph
(b) h = -a (e) g = -d (h) j = -b
(c) (f)
n = -2a i=-2d
Answers to the Exercises 545
546 Foundation Maths for Engineers
4. Vector Magnitude Direction (bearing)
a 1N 270° b 1.4N 135° c 1.1N 117° d 1.4N 045° e 2N 0900
f 1.4N 045° g 1.4N 225° h lN 090°
2.8N 215° j 1.4N 315° k l.lN 117° I 2.1N 045° m 2.8N 045° n 2N 090°
Giving the direction of a vector as a bearing provides a unique answer.
Exercise 11.2.2
1. LJ ... ~ a e
g
m
7\ e
Answers to the Exercises 547
2. This solution depends on your choice of a and b
D
3. 13 newtons; angle = 22.6° to larger force. 4. 15.5 newtons; angle = 29.6° to smaller force. 5. 100.9 miles on bearing 112°
Exercise 11.3 .1
1. [20 cos 30°] = [10v'3] 20 COS·60° 10
[ 250 cos 70°] [ 85.5] 2• 250 cos 20° = 234.9
3. F = [ O J · G = [ 75 J 100 ' 0
Exercise 11.3.2
1. [ =~~ ::: ~~:] -[ -~;~3] 2. r-30 cos 70°J = [-10.26J
-30 cos 20° -28.18
548 Foundation Maths for Engineers
3. Vector Component form
a [ -~] b [ _;J c [ -~.5 J d GJ e [~] f GJ g [ =:J h [~] i [ =~J j [ -:] k [ -~.5 J
[1.5] l 1.5 m GJ n [~]
Answers to the Exercises 549
Exercise 11.3.3
Direction Vector Magnitude bearing a (see p.418)
a 5 036.9° 53.1° b 13 022.6° 67.4° c 5 323.1° 126.9° d Y5 206.6° -116.6° e V2 225° -135°
I Y10 161.6° -71.6°
Exercise 11.3.4
2. Direction
Vector Magnitude bearing or a (see p.418)
a+ b = [ 1!] 8V5 026.6° 63.4°
b + c = [ 1!] 2Y65 007.1° 82.9°
a+c=[~] 8 oo goo
c +I= [ -~] Y5 296.6° 153.4°
d-e=[-~] 1 180° -90°
c- a= [ -~] 6 270° 180°
b+e=[1:] V137 020° 70°
I- e = [ -~J 2V2 135° -45°
3. (a) ( 5 cos 4SO ) 5 cos 45°- 4
3.6N, -7S
(b) c- 3 cos 30°) 3 cos 60°- 2
0.78N, -140.1°
550 Foundation Maths for Engineers
(5.3 cos 30° - 4.7 cos 60° )
(c) 5.3 cos 60° + 4.7 cos 30°- 6
(4 cos 45° + 5 cos 30° - 3)
(d) 4 cos 45° - 5 cos 60°
2.35N, 17.8°
4.17N, 4S
4. ------------------------------------------Direction
Vector Magnitude bearing or a (see p.418)
a+ b = [ -~J v'13 123.7° -33.7°
b+c=[-~] 1 180.0 -90°
a-b=[-~] v'65 352.9° 97.1°
3a+2b=[-~] v'50 098.1° -8.1°
[ -16] - 2a - 3b + 4c = 25 29.7 327.4 123.6°
Exercise 11.3.5
1. 2i, 5i, 4i, I, 7 .3i 2. a= 3i + j
b = -i + 3j c = -3i- 2j d=3i+j
3. I a I = 5, I b I = v'B, I c I = 5
c
II
II X
4. Same as Exercise 11.3.4, Problem 4. 5. (a) (3 - 2.5 COS 30°)i + (2- 2.5 cos 60°)i = 0.83i + 0.75j
(b) (5.3 COS 30°- 4.7 COS 60°)i + (5.3 COS 60° + 4.7 cos 30° - 6)j = 2.24i + 0.72j
(c) (7.1 cos 15°- 5.4 cos 80°- 8cos 60° + 4.1cos 40°)i + (7.1 cos 75° + 5.4 cos 10°- 8 cos 30° - 4.1 cos 50°)j = 5.06i - 2.41j
Exercise 11.4.1
1. a = j b = i c = - 2i + 3j d = -i- 2j
c
b
d
2. c = 3i + 4j; f = 3i + 4j; d = 3i + 4j; c is the position vector of (3, 4)
3. a = i + 2j; b = 5i + j; c = 7i + Sj ~
AB=b-a=4i-j oc = c - b = 2; + 7i ___,. CA =a- c = -6i- 6j
4. a = 4i + 2j; b = 5i + 4j; AB = i + 2j ~ I AB I = V5, direction = 63.4°
Exercise 11.4.2
1. Case Velocity Acceleration
t=O t=l t=O t=1
(a) (b) (c)
3i lOi + lOj wj
6i + Bj lOi + 0.2j (w- g)j
Si -9.8j -gj
6i + Bj -9.8j -gj
speed at timet = 0 is (a) 3 ms- 1 (b) 10Y2 ms- 1 (c) w ms- 1
(3 (3t3 ) 2. v = ri - (3t - 2)j; r = 3 i - 2 - 2t j
3. v = -dw sin wti + dw cos wtj a= -dw2 cos wt i- dw2 sin wtj a = - w2r hence a is parallel to r
Answers to the Exercises 551
552 Foundation Maths for Engineers
Vector
a+b
a-b
2a- 3b
Objective Test 11
1. Scalars: area, temperature, volume, energy, time; vectors: velocity, force, displacement, acceleration
2.
3. a = [~] or a = 3i
[ 2.5 J 5\1'3 b = 5\1'3/ 2 or b = 2.5i + - 2-j
Direction Component form Magnitude bearing or a
[ 5.5 J 5\1'3 5\1'3/ 2 or 5.5i + - 2-j 7 052° 38.2°
[ 0.5 J 5\1'3 y' ( or 0.5i - --j -5 3 2 2
4.36 173.4° -83.4°
[ -1.5 J 15\1'3 -15\1'3/2 or -1.5i- -2-j 13.1 186.6° -96.6°
4. (3 cos 45° - 4 cos 60° - 2)i + (3 cos 45° + 4 cos 30° - 8)j = -1.879i- 2.415j; magnitude= 3.06 N; direction 217.9° or a= -127.9°
5. 18.5 knots bearing 240.3° 6. 12.4 km bearing 108° 7. r(t) = (t3 + t)i- (2t2 + 2t)j, a(t) = 6ti - 4j
CHAPTER 12
Exercise 12.2.1
Exercise 12.3.1
[_:] 2. [ 0.4 -0.1] -0.3 -0.7
4. 3 [ -~ -~J 1 5. - [4 1 -2)
8
6. X [ 3
\ ] a -x
10 2
8 [ ln 10. [a + 2b 2a + 3b 3a + 4b]
[0 -0.5] 11. 2.3 -2.4
13 [ ~] 5
16. a = 6, b = - -3
Exercise 12.4.1
1. [ -~ ~] [:] = [~]
7. [ =:~]
9. [3x +By] 2y- X
[ 0 -5] 12. 23 -24
[ -8 1 0 ] 14.
3 3 0
2 5 0
17. x = 5, m = 2
Answers to the Exercises 553
554 Foundation Maths for Engineers
3. [-~ ~ J [; J = [: J
Exercise 12.5.1
1. 1 2. 2y- 3x 6. 3; (3, 0) 8. 4; -1.25, 3.75
10. 0, no unique solution
Exercise 12.5.2
1. 27 4. 4
Exercise 12.5.3
1. 0
2 8.
15
Exercise 12.5.4
2. 1 5. -18
2. 0
9. 0
1. X= 0, y = 0.7, Z = 0.3
3. 1 4. 0 5. 1 7. -10; (2, 3) 9. 22; (2.7, 1.8)
3. -0.018 6. xy(y- x) 7. 3
3. 0 7. -1860
10. -y(z- xf
2. det M = 0, so no unique solution 3. a = -2, b = 2, c = 1
Exercise 12.6.1
1 [v'3 -1 J 2" 4' 4 1 v'3
-1, [ ~ 1
-~] 3. 0, no inverse 4. -2 -1 1 -1
[ Va 0 0 ] 61.u -k kn-m]
5. abc, ~ 1/b 0 1 -n
0 1/c 0 1
Exercise 12.6.2
1. X = 2, y = 3 2. S = 2, t = 3 3. X = 5, y = -4 4. X= -1, y = 5 5. X= 0, y = 2, Z = -1 6. p = 0.3, q = 0.5, r = 0.2
Exercise 12. 7.1
1. X = 2, y = -1, Z = 4 3. u = 1, v = 0.5, w = 2.5
2. X= -0.7, y = 0.2, Z = 0.5 4. p = 5, q = 1, r = 0
Exercise 12.8.1
1. inconsistent, no solutions
3 + A 2. Infinitely many solutions: u = -- , v = A
6
3. Inconsistent, no solutions
4 + A (1 + 4A) 4. Infinitely many solutions: x = - 6- , y = - 3 , z = A
5. u = 8 - 4A, v = 3(A - 1), w = A
Exercise 12.9.1
1. Currents (A): 0.581, -0.452, 1.032; Voltages (V): 2.903, -0.903, 3.097 across AB, BC and BD.
2. Currents (rnA): -0.243, 0.054, -0.297 Voltages (V): -1.216, 0.216, -1.784 across AB, BC and BD.
3. Currents (rnA): 0.415, -0.418, -0.727, 0.564, 0.309; Voltages (V): 0.873, -0.418, -1.455, 1.127, 1.545 across AB, BC, CD, BF and CE.
4. Currents (A): 0.343, 0.214, 0.129, 1.000; Voltages (V): 1.714, 1.286, 1.288, 4.000 across AB, BC, BD, EF
5. Currents (A): 0.75, 0.25, 0.5,1.5, -0.75; Voltages (V): 1.5, 1.5, 1.5, 3.0, -3.0 across AB, BC, BD, DF, EF.
Objective Test 12
1. (a) [ -0.6 1.2] 0.8 -0.6
[ 1.5 (b) -0.7
-1.2] -0.3
[ 0.13 0.04 J (c) -0.46 0.29
[0.17 (d) 0.20
-0.68] 0.25
u 0 n 2. 1
0
Answers to the Exercises 555
556 Foundation Maths for Engineers
5. p = 11, q = 42 6. -15
[ 0.1 0.3] 7. det M = 0.2; M- 1 = 5 -0.6 0.2
8. X = 1.5, y = 11 9. X= -3, y = 0, Z = 4
3- 5A 10. u = , v =A
2
Index
abscissa 7 adjoint matrix 453 amplitude 108, 124 angle convention 109 angular frequency 122 AP 176 areas 296
negative 304 arithmetic progression 176 associative 415 asymptote 80, 113, 288, 291 average
rate of change 228, 233 speed 228, 229
base 69 beats 143, 158 binomial theorem 218, 221, 222,
484 bound vector 424 boundary conditions 370
calculus, fundamental theorem of 317
centroid 358 chain rule 252, 485 check sums 458 codomain 75 coefficient 35, 217 cofactor 452 combinations 220 common difference 177, 485 common ratio 182, 485 commutative 415 completing the square 46 components 416 composite function 77
differentiation 252 continuous 81 convergence 56, 398, 401 coordinates 6 cosecant 132, 145, 486 cosine
as a projection 110 differentiation 275, 486 general solutions 118, 135
integration 320, 487 period 120, 134 primary and secondary
solutions 115 rule 164
cotangent 132, 145, 486 Cramer's rule 440, 447 cubic 51 current 468, 474 curve sketching 286
decay constant 94 decay process 87, 232
and differential equations 384 half life 94
decimal search 54 definite intergral 313, 319 degree 51 denominator 204 dependent variable 5 derivative 242
second 247 determinant
of a 2x2 matrix 439, 491 of a 3x3 matrix 442 meaning of zero value 465
differentiation applications 248, 258, 269, 286 constant 242 chain rule 252, 485 composite functions 252, 485 differences 244 exponential functions 281, 283,
486 function of a function 252, 485 functional notation 246 limiting process 237 logarithmic functions 284, 486 maxima and minima 258 multiples 244 product rule 267, 486 quotient rule 267, 486 rules 242, 252, 267 substitution 252 sums 244 trigonometric functions 273, 486
557
558 Index
differential equations 367 analytical solution 376 direction fields 372 Euler's method 385 general solution 369 initial conditions 370 numerical solution 384 order of 368 particular solution 369 separation of variables 376 setting up 379
direct proportion 2, 19 direction fields 372 discontinuous 81 discriminant 49 displacement 231, 302, 410 distance 231 divergence 58 domain 75
e 85 electric circuits 468 elimination 458
check sums 458 multipliers 461 pivots 460 valid steps 459
empirical model 476 equation
normal 250 quadratic 34 straight line 9, 14 tangent 250
errors 393 absolute 394 estimation 396 propagation 395 relative 394 rounding 393
Euler's method 385, 387 even function 114 exponent 69
laws 70, 484 exponential equations 74 exponential form 69 exponential functions 83, 85
differentiation 281 integration 320
exponential law 102 extrapolation 29
factors 40 factor theorem 198, 201 factorials 219 factorizing 42, 198, 201 force 409 formula iteration 55
free vector 424 frequency 137 function 76
composite 77 continuous/discontinuous 81 even 114 decay 83, 87 exponential 83 growth 83, 87 inverse 79 logarithmic 88 odd 114 periodic 108, 118, 121 sinusoidal 121
functional notation for derivatives 246
fundamental theorem of calculus 317
general solutions differential equations 369 trigonometric equations 118
geometric progression (GP) 181 geometric sequence 181 gradient 10, 84, 239, 242
normal 250 rate of change 15 straight line 10 tangent 239, 250
graphical model 8 graphs
growth process 87 reduction to straight line 100 sketching 286 straight line 9, 14
half angle substitution 340 half life 94
identities trigonometric 144, 167, 489
identity matrix 435 image 75 improper partial fractions 204, 213 improved Euler method 388 indefinite integral 320 identity
double angle 150 sum and difference 148 trigonometric 145, 167
independent variable 5 index 69
laws 70, 484 inflexion 52, 261 initial conditions 370 instantaneous rate of change 228,
234, 242
instantaneous speed 228 integral
definite 319 indefinite 320 logarithmic form 336 trigonometric substitutions 338,
340 integration
as an area 297 by parts 344, 346, 488 by quadrature 403 by substitution 327, 332, 338,
342 exponential functions 321, 322,
487 fractions 330, 336 numerical 402, 488 partial fractions 351 polynomials 315, 320, 321, 330,
487 relation to differentiation 317 trigonometric functions 320,
322, 487 volumes 355
intercept 12, 38 interference 142 interpolation 29 intervals 3 mverse
function 79, 155 matrix 450, 453, 491 proportion 3, 23 square law 25 trigonometric functions 155, 338
irreducible quadratics 202
Kirchhoff's laws 468, 474
limit of a sequence 172 of sin xlx 273
limiting process 237 line of best fit 27 linear
equation 14 extrapolation 29 factors 40 interpolation 29 law 26 relation 2
local maximum or minimum 52, 261
long division of polynomials 192 logarithm
base 88 base e 89 base ten 89
common 89 differentiation 284 graph paper 100 law 103 natural 89 rules 92, 484
logarithmic integral 336 log-linear graph paper 104 log-log graph paper 100 loop current 468 lower sum 307
magnitude of a vector 410 matrices 430
addition 433 adjoint 453 cofactor 452 identity 435, 453, 491 inverse 450, 453, 491 minor 443, 452 products 434 subtraction 433 transpose 451
maximum 37, 52, 252, 261, 269 mesh current 468 minimum 37, 52,252,261, 269 modelling 26, 473
assumptions 475 empirical 474 exponential laws 102 graphical 8 linear laws 26 polynominals 60 power laws 99 quadratic 60 simplification 475 validation 475
moments 359
negative angles 109 negative areas 302 Newton-Raphson method 400,
489 non- singular systems 465 numerical methods 392
decimal search 54 finding roots 54, 400 for differential equations 384 formula iteration 55 integration 402
numerator 204
Ohm's law 22, 468 odd function 114 ordinate 7
Index 559
560 Index
parabola 35 parallelogram law 414 partial fractions 204, 215
applied to integrals 351 improper 204 proper 204
particular solution 369 Pascal's triangle 216 period 108, 120, 134 phase angle 126 phasor 112 point of inflexion 52, 260 polynomial
coefficient 51 cubic 51 degree 51 division 192 irreducible 202 linear 51 models 60 quadratic 34 quartic. 51
position vector 424 power 67, 69
fractional 67, 72 laws 70, 98, 484 negative 68, 71
primary solution 115 principal values 156 product rule 267, 488 proportionality
constant of 21 direct 2, 18 general 24 inverse 22
quadratic completing the square 46 equation 34 factorizing 42 formation 40 formula 48, 484 graph 36 law 34 roots 38, 45, 48
quartic 51 quotient 193, 195 quotient rule 267, 486
radian 133 range 75 rate of convergence 398 rates of change 15, 84
average 233 gradient 15 instantaneous 234
reciprocal 71
rectangle rule 300 recurrence relation 170 remainder 193, 195
theorem 197, 201 roots 45, 52
by decimal search 54 by formula iteration 55 by graph plotting 53 by Newton-Raphson
method 400 by 'quadratic formula' 48
scalar 410 secant 132, 145, 486 second derivative 247 secondary solution 115 semi-log graph paper 104 separation of variables 376 sequence 170 series 174 setting up differential
equations 379 Simpson's rule 403, 488 simultaneous equations
Cramer's rule 440, 447 elimination 458 infinitely many solutions 464 matrices 437, 455 non-singular solution 465 singular system 465 types of solution 465 unique solution 465
sine as a projection 110 differentiation 274, 486 graph 112 integration 321, 487 p~riod 120 primary and secondary
solutions 115 rule 161
singular systems 465 SI units 483 slope 10, 84 solid of revolution 355 speed 227,231,427 standard index form 68 stationary points 258
classification 261 steady state 87 straight line graphs 9, 14
gradient 10 intercept 12
sum lower 207 of cubes 176 of first n integers 176