| Date | November 2009 | Marks available | 1 | Reference code | 09N.1.sl.TZ0.6 |
| Level | SL only | Paper | 1 | Time zone | TZ0 |
| Command term | Find | Question number | 6 | Adapted from | N/A |
Question
Let \(f (x) = 2x^2 + x - 6\)
Find \(f'(x)\).
Find the value of \(f'( - 3)\).
Find the value of \(x\) for which \(f'(x) = 0\).
Markscheme
\(f'(x) = 4x + 1\) (A1)(A1)(A1) (C3)
Note: Award (A1) for each term differentiated correctly.
Award at most (A1)(A1)(A0) if any extra terms seen.
[3 marks]
\(f'( - 3) = - 11\) (A1)(ft) (C1)
[1 mark]
\(4x + 1 = 0\) (M1)
\(x = - \frac{{1}}{{4}}\) (A1)(ft) (C2)
[2 marks]
Examiners report
This was a fairly standard question. However, some candidates found f (−3) instead of \(f'\)(−3). Quite a few candidates were unable to answer part (c) as they tried to find \(f'\)(0) instead of finding x when \(f'\)(x) = 0.
This was a fairly standard question. However, some candidates found f (−3) instead of \(f'\)(−3). Quite a few candidates were unable to answer part (c) as they tried to find \(f'\)(0) instead of finding x when \(f'\)(x) = 0.
This was a fairly standard question. However, some candidates found f (−3) instead of \(f'\)(−3). Quite a few candidates were unable to answer part (c) as they tried to find \(f'\)(0) instead of finding x when \(f'\)(x) = 0.
