Graph of Function2

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2.2 SOLUTION OF EQUATIONS BYTHE GRAPHICAL METHOD

Section B (Optional)

12 marks


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SUGGESTED TIME

15 20 MINUTES

PER QUESTION


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12 (a) Complete table 1 in the answer space for the equation y

=2x2-x-3. ( 2 marks)

x -2 -1 -0.5 1 2 3 4 4.5 5

y 7 -2 -2 3 12 33 42

3122 3 xxy12 (a) In the table 1 , find the value of m and the value of n

for the equation ( 2 marks)

x -3 -2 -1 0 1 2

y -15 m 13 3 -7 n


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12 (a) Complete table 1 in the answer space for the equation y

=2x2-x-3. ( 2 marks)

x -2 -1 -0.5 1 2 3 4 4.5 5

y 7 -2 -2 3 12 33 42

0 25


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1. Fill in the blanks in the table

GRAPHS OF FUNCTIONS12

3122 3 xxy

-2 2

m

x

y

n

11 5


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53 x

Scales and the range of x are given

Plot the points accurately

Can use flexible curve

2. Draw the graphs of functions
http://f/User/My%20Documents/Graph%20plot.doc


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the curve must be smooth, passingthrough each point

through
http://f/User/My%20Documents/graf%2012b.jpg


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losing marks

Using your own scale

12 marks 1 mark
http://f/User/My%20Documents/graf%20hilang%20markah.jpg


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-10

-15-20


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http://f/User/My%20Documents/jadual%2012%20PLOTTING.jpg


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http://f/User/My%20Documents/jadual%2012%20PLOTTING.jpg


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12c.

x =1.5

Write the answer in the answer spaces provided


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12c. The first equation from (a)

eliminate variables that have indices ,

562 xxy

472

xx

The second equation from (c)

x

xx

1,,

32
http://f/User/My%20Documents/graph%20no%2012.ppt


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12c. The first equation from (a)

eliminate variables that have indices

562 xxy

472

xx

The second equation from (c)

9134576

)47(56

22

22

xy

xxxxy

xxxxy


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12d.


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Steps involved in solving an

equation graphically :Determine the two graphs to be drawn.

Draw the two graphs on the same axes.

Determine the solutions by reading off the

x-coordinates of the point of intersection of

the two graphs.


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Examp le :[ SPM, Nov 04, P2, Q12 ]

a) Complete the following table for the equation

.742 2 xxy

x - 2 - 1 0 1 2 3 4 4.5 5

y - 1 - 7 - 9 - 7 9 15.5 2.3

b) By using a scale of 2 cm to 1 unit on the x-axis

and 2 cm to 5 units on the y-axis, draw the graph of

c) From your graph, findi. the value ofywhen x= - 1.6

ii. the value ofxwhen y= - 3

. State the value ofx.

52for742 2 xxxy


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d) Draw a suitable straight line on your graph

to find a value x which satisfies the equation

for0272 2 x 52 x


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Solution :

17)3(4)3(22

y

a) x= 2,

97)2(4)2(2 2 y

x= 3,

x - 2 - 1 0 1 2 3 4 4.5 5

y 9 - 1 - 7 - 9 - 7 -1 9 15.5 2.3


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-2 -1 1 32 4 5

5

10

15

25

20

5

10

15

x

y

ywhen

x= - 1.6

xwhen

y= - 3


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d)

0272 2 x Given equation

.742 2 xxy Graph drawn

.742 2 xxy

2720 2 x

204 xy (Straight line to be drawn)


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-2 -1 1 32 4 5

5

10

15

25

20

5

10

x

y

204 xy

Intersection

point