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Date May Example questions Marks available 6 Reference code EXM.1.AHL.TZ0.3
Level Additional Higher Level Paper Paper 1 (without calculator) Time zone Time zone 0
Command term Express Question number 3 Adapted from N/A

Question

Let f(x)=4x5x23x+2     x1,x2.

Express f(x) in partial fractions.

[6]
a.

Use part (a) to show that f(x) is always decreasing.

[3]
b.

Use part (a) to find the exact value of 01f(x)dx, giving the answer in the form lnq,   qQ.

[4]
c.

Markscheme

f(x)=4x5(x1)(x2)Ax1+Bx2   M1A1

4x5A(x2)+B(x1)      M1A1

x=1A=1      x=2B=3      A1A1

f(x)=1x1+3x2

[6 marks]

a.

f(x)=(x1)23(x2)2   M1A1

This is always negative so function is always decreasing.     R1AG

[3 marks]

b.

011x1+3x2 dx=[ln|x1|+3ln|x2|]01   M1A1

=(3ln2)(ln2+3ln3)=2ln23ln3=ln427    A1A1

[4 marks]

c.

Examiners report

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a.
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b.
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c.

Syllabus sections

Topic 1—Number and algebra » AHL 1.11—Partial fractions
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Topic 1—Number and algebra

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