| Date | May 2018 | Marks available | 1 | Reference code | 18M.1.sl.TZ1.1 |
| Level | SL only | Paper | 1 | Time zone | TZ1 |
| Command term | Write down | Question number | 1 | Adapted from | N/A |
Question
Let \(f\left( x \right) = \sqrt {x + 2} \) for x ≥ 2 and g(x) = 3x − 7 for \(x \in \mathbb{R}\).
Write down f (14).
[1]
a.
Find \(\left( {g \circ f} \right)\) (14).
[2]
b.
Find g−1(x).
[3]
c.
Markscheme
f (14) = 4 A1 N1
[1 mark]
a.
attempt to substitute (M1)
eg g (4), 3 × 4 − 7
5 A1 N2
[2 marks]
b.
interchanging x and y (seen anywhere) (M1)
eg x = 3y − 7
evidence of correct manipulation (A1)
eg x + 7 = 3y
\({g^{ - 1}}\left( x \right) = \frac{{x + 7}}{3}\) A1 N3
[3 marks]
c.
Examiners report
[N/A]
a.
[N/A]
b.
[N/A]
c.
