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Date November 2013 Marks available 3 Reference code 13N.2.sl.TZ0.2
Level SL only Paper 2 Time zone TZ0
Command term Find Question number 2 Adapted from N/A

Question

Let \(f(x) = (x - 1)(x - 4)\).

Find the \(x\)-intercepts of the graph of \(f\).

[3]
a.

The region enclosed by the graph of \(f\) and the \(x\)-axis is rotated \(360^\circ\) about the \(x\)-axis.

Find the volume of the solid formed.

[3]
b.

Markscheme

valid approach     (M1)

eg     \(f(x) = 0\), sketch of parabola showing two \(x\)-intercepts

\(x = 1,{\text{ }}x = 4{\text{   }}\left( {{\text{accept (1, 0), (4, 0)}}} \right)\)     A1A1     N3

[3 marks]

a.

attempt to substitute either limits or the function into formula involving \({f^2}\)     (M1)

eg     \(\int_1^4 {{{\left( {f(x)} \right)}^2}{\text{d}}x,{\text{ }}\pi \int {{{\left( {(x - 1)(x - 4)} \right)}^2}} } \)

\({\text{volume}} = 8.1\pi {\text{   (exact), 25.4}}\)     A2     N3

[3 marks] 

b.

Examiners report

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

Syllabus sections

Topic 6 - Calculus » 6.5 » Volumes of revolution about the \(x\)-axis.
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