| Date | May 2016 | Marks available | 2 | Reference code | 16M.2.hl.TZ1.2 |
| Level | HL only | Paper | 2 | Time zone | TZ1 |
| Command term | Write down | Question number | 2 | Adapted from | N/A |
Question
Express \({x^2} + 4x - 2\) in the form \({(x + a)^2} + b\) where \(a,{\text{ }}b \in \mathbb{Z}\).
[2]
a.
If \(f(x) = x + 2\) and \((g \circ f)(x) = {x^2} + 4x - 2\) write down \(g(x)\).
[2]
b.
Markscheme
\({(x + 2)^2} - 6\) A1A1
[2 marks]
a.
\((g \circ f)(x) = {(x + 2)^2} - 6\) (M1)
\( \Rightarrow g(x) = {x^2} - 6\) A1
[2 marks]
b.
Examiners report
Well done by most candidates.
a.
Well done by most candidates. Those students who lost marks on this question tended to do so in part (b), seemingly through misinterpreting the question.
b.
Syllabus sections
Topic 2 - Core: Functions and equations » 2.1 » Concept of function \(f:x \mapsto f\left( x \right)\) : domain, range; image (value)
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