Oxford Admissions Test 2008

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OXFORD UNIVERSITYMATHEMATICS, JOINT SCHOOLS AND COMPUTER SCIENCE

WEDNESDAY 5 NOVEMBER 2008

Time allowed: 212 hoursFor candidates applying for Mathematics, Mathematics & Statistics,

Computer Science, Mathematics & Computer Science, or Mathematics & Philosophy

Write your name, test centre (where you are sitting the test), Oxford college(to which you have applied or been assigned) and your proposed course (fromthe list above) in BLOCK CAPITALS.

NOTE: Separate sets of instructions for both candidates and test supervisors

are provided, which should be read carefully before beginning the test.

NAME:

TEST CENTRE:

OXFORD COLLEGE (if known):

DEGREE COURSE:

DATE OF BIRTH:

FOR TEST SUPERVISORS USE ONLY:

[ ] Tick here if special arrangements were made for the test.Please either include details of special provisions made for the test and the reasons for

these in the space below or securely attach to the test script a letter with the details.

Signature of Invigilator

FOR OFFICE USE ONLY:

Q1 Q2 Q3 Q4 Q5 Q6 Q7 Total


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1. For ALL APPLICANTS.

For each part of the question on pages 37 you will be given four possible answers,just one of which is correct. Indicate for each part AJ which answer (a), (b), (c),or (d) you think is correct with a tick (X) in the corresponding column in the table

below. Please show any rough working in the space provided between the parts.

(a) (b) (c) (d)

A

B

C

D

E

F

G

H

I

J

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A. The function = 23 62 + 5 7

has

(a) no stationary points;(b) one stationary point;(c) two stationary points;(d) three stationary points.

B. Which is the smallest of these values?

(a) log10 (b)p

log10 (2) (c) 1

log10 3

(d)1

log10

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C. The simultaneous equations in ,

(cos ) (sin ) = 2(sin ) + (cos ) = 1

are solvable

(a) for all values of in the range 0 6 2;(b) except for one value of in the range 0 6 2;(c) except for two values of in the range 0 6 2;(d) except for three values of in the range 0 6 2.

D. When1 + 3 + 52 + 73 + + 9949

is divided by 1 the remainder is

(a) 2000 (b) 2500 (c) 3000 (d) 3500

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E. The highest power of in

h26 + 7

3+

38 124i5

+h

35 1225

+

7 + 64i63

is(a) 424 (b) 450 (c) 500 (d) 504

F. If the trapezium rule is used to estimate the integral

Z10

() d

by splitting the interval 0 6 6 1 into 10 intervals then an overestimate of the integralis produced. It follows that

(a) the trapezium rule with 10 intervals underestimatesR10

2() d;

(b) the trapezium rule with 10 intervals underestimatesR10

(() 1) d;

(c) the trapezium rule with 10 intervals underestimatesR21

( 1) d;

(d) the trapezium rule with 10 intervals underestimatesR10

(1 ()) d

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G. Which of the graphs below is a sketch of

=1

4 2 5?

x

y

x

y

(a) (b)

x

y

x

y

(c) (d)

H. The equation9 3+1 =

has one or more real solutions precisely when

(a) > 94 (b) 0 (c) 6 1 (d) > 58

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I. The function () is dened for positive integers by

() = sum of the digits of .

For example, (723) = 7 + 2 + 3 = 12 The sum

(1) + (2) + (3) + + (99)

equals(a) 746 (b) 862 (c) 900 (d) 924

J. In the range 0 6 2 the equation

(3 + cos )2 = 4 2sin8

has

(a) 0 solutions (b) 1 solution (c) 2 solutions (d) 3 solutions

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(i) Find a pair of positive integers, 1 and 1 that solve the equation

(1)2 2 (1)

2 = 1

(ii) Given integers we dene two sequences 1 2 3 and 1 2 3 by setting

+1 = 3 + 4 +1 = + for > 1

Find positive values for such that

(+1)2 2 (+1)

2 = ()2 2 ()

2

(iii) Find a pair of integers which satisfy 2 22 = 1 such that 50

(iv) (Using the values of and found in part (ii)) what is the approximate value of as increases?

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3.

For APPLICANTS IN

MATHEMATICS

MATHEMATICS & STATISTICS

MATHEMATICS & PHILOSOPHY

MATHEMATICS & COMPUTER SCIENCE

ONLY.

Computer Science applicants should turn to page 14.

(i) The graph = () of a certain function has been plotted below.

x

y

On the next three pairs of axes (A), (B), (C) are graphs of

= () ( 1) ()

in some order. Say which axes correspond to which graphs.

x

y

(A)

x

y

(B)

x

y

(C)

(ii) Sketch, on the axes opposite, graphs of both of the following functions

= 22

and = 222

Carefully label any stationary points.

(iii) Let be a real number and dene the following integral

() =

Z10

2()2

d

State the value(s) of for which () is largest. Briey explain your reasoning.[Note you are not being asked to calculate this maximum value.]

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6

-

p p p

p p p

p

p

p

p

p

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4.

For APPLICANTS IN

MATHEMATICS

MATHEMATICS & STATISTICS

MATHEMATICS & PHILOSOPHY

ONLY.

Mathematics & Computer Science and Computer Science applicants should turn to

page 14.

C

p

q

P

Q

O x

y

Let and be positive real numbers. Let denote the point ( 0) and denote thepoint (0 )

(i) Show that the equation of the circle which passes through , and the origin is

2

+ 2

= 0Find the centre and area of .

(ii) Show thatarea of circle

area of triangle >

(iii) Find the angles and if

area of circle

area of triangle = 2

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The Millennium school has 1000 students and 1000 student lockers. The lockers are ina line in a long corridor and are numbered from 1 to 1000.

Initially all the lockers are closed (but unlocked).

The rst student walks along the corridor and opens every locker.

The second student then walks along the corridor and closes every second locker, i.e.closes lockers 2, 4, 6, etc. At that point there are 500 lockers that are open and 500 thatare closed.

The third student then walks along the corridor, changing the state of every third locker.Thus s/he closes locker 3 (which had been left open by the rst student), opens locker

6 (closed by the second student), closes locker 9, etc.All the remaining students now walk by in order, with the th student changing thestate of every th locker, and this continues until all 1000 students have walked alongthe corridor.

(i) How many lockers are closed immediately after the third student has walked alongthe corridor? Explain your reasoning.

(ii) How many lockers are closed immediately after the fourth student has walked alongthe corridor? Explain your reasoning.

(iii) At the end (after all 1000 students have passed), what is the state of locker 100?Explain your reasoning.

(iv) After the hundredth student has walked along the corridor, what is the state oflocker 1000? Explain your reasoning.

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6.

For APPLICANTS IN

COMPUTER SCIENCE

MATHEMATICS & COMPUTER SCIENCE

ONLY.

(i) A, B and C are three people. One of them is a liar who always tells lies, another is

a saint who always tells the truth, and the third is a switcher who sometimes tells thetruth and sometimes lies. They make the following statements:

A: I am the liar.B: A is the liar.C: I am not the liar.

Who is the liar among A, B and C? Briey explain your answer.

(ii) P, Q and R are three more people, one a liar, one a saint, and the third a contrarianwho tells a lie if he is the rst to speak or if the preceding speaker told the truth, butotherwise tells the truth. They make the following statements:

P: Q is the liar.Q: R is the liar.R: P is the liar.

Who is the liar among P, Q and R? Briey explain your answer.

(iii) X, Y and Z are three more people, one a liar, one a switcher and one a contrarian.They make the following statements:

X: Y is the liar.Y: Z is the liar.Z: X is the liar.X: Y is the liar.Y: X is the liar.

Who is the liar among X, Y and Z? Briey explain your answer.

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7. For APPLICANTS IN COMPUTER SCIENCE ONLY.

Ox-words are sequences of letters and that are constructed according to the followingrules:

I. The sequence consisting of no letters is an Ox-word.

II. If the sequence is an Ox-word, then the sequence that begins with , followedby and ending in , written , is an Ox-word.

III. If the sequences and are Ox-words, then the sequence followed by , written, is an Ox-word.

All Ox-words are constructed using these rules. The length of an Ox-word is the numberof letters that occur in it. For example and are Ox-words of length 4.

(i) Show that every Ox-word has an even length.

(ii) List all Ox-words of length 6.

(iii) Let be an Ox-word. Is the number of occurrences of in necessarily equal tothe number of occurrences of in ? Justify your answer.

You may now assume that every Ox-word (of positive length) can be written uniquelyin the form 0 where and 0 are Ox-words.

(iv) For > 0, let be the number of Ox-words of length 2. Find an expression for+1 in terms of 0 1 . Explain your reasoning.

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Oxford Admissions Test 2008