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Date May 2014 Marks available 4 Reference code 14M.1.sl.TZ2.15
Level SL only Paper 1 Time zone TZ2
Command term Write down Question number 15 Adapted from N/A

Question

A function is given as \(f(x) = 2{x^3} - 5x + \frac{4}{x} + 3,{\text{ }} - 5 \leqslant x \leqslant 10,{\text{ }}x \ne 0\).

Write down the derivative of the function.

[4]
a.

Use your graphic display calculator to find the coordinates of the local minimum point of \(f(x)\) in the given domain.

[2]
b.

Markscheme

\(6{x^2} - 5 - \frac{4}{{{x^2}}}\)     (A1)(A1)(A1)(A1)     (C4)

 

Note: Award (A1) for \(6{x^2}\), (A1) for \(–5\), (A1) for \(–4\), (A1) for \({x^{ - 2}}\) or \(\frac{1}{{{x^2}}}\).

     Award at most (A1)(A1)(A1)(A0) if additional terms are seen.

 

[4 marks]

a.

\((1.15,{\text{ }} 3.77)\) \(\left( {{\text{(1.15469..., 3.76980...)}}} \right)\)     (A1)(A1)     (C2)

 

Notes: Award (A1)(A1) for “\(x = 1.15\) and \(y = 3.77\)”.

     Award at most (A0)(A1)(ft) if parentheses are omitted.

 

[2 marks]

b.

Examiners report

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

Syllabus sections

Topic 7 - Introduction to differential calculus » 7.2 » The derivative of functions of the form \(f\left( x \right) = a{x^n} + b{x^{n - 1}} + \ldots \), where all exponents are integers.
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