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Date May 2014 Marks available 4 Reference code 14M.2.hl.TZ2.7
Level HL only Paper 2 Time zone TZ2
Command term Find Question number 7 Adapted from N/A

Question

The function f is defined as \(f(x) =  - 3 + \frac{1}{{x - 2}},{\text{ }}x \ne 2\).

(i)     Sketch the graph of \(y = f(x)\), clearly indicating any asymptotes and axes intercepts.

(ii)     Write down the equations of any asymptotes and the coordinates of any axes intercepts.

[4]
a.

Find the inverse function \({f^{ - 1}}\), stating its domain.

[4]
b.

Markscheme


     A1A1A1

 

Note:     Award A1 for correct shape, A1 for \(x = 2\) clearly stated and A1 for \(y =  - 3\) clearly stated.

 

x intercept (2.33, 0) and y intercept (0, –3.5)     A1

 

Note:     Accept –3.5 and 2.33 (7/3) marked on the correct axes.

 

[4 marks]

a.

\(x =  - 3 + \frac{1}{{y - 2}}\)     M1

 

Note:     Award M1 for interchanging x and y (can be done at a later stage).

 

\(x + 3 = \frac{1}{{y - 2}}\)

\(y - 2 = \frac{1}{{x + 3}}\)   M1

 

Note:     Award M1 for attempting to make y the subject.

 

\({f^{ - 1}}(x) = 2 + \frac{1}{{x + 3}}\left( { = \frac{{2x + 7}}{{x + 3}}} \right),{\text{ }}x \ne  - 3\)     A1A1

 

Note:     Award A1 only if \({f^{ - 1}}(x)\) is seen. Award A1 for the domain.

 

[4 marks]

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Topic 2 - Core: Functions and equations » 2.1 » Inverse function \({f^{ - 1}}\), including domain restriction. Self-inverse functions.

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