OCR MEI C2 — Question 4 5 marks

Exam BoardOCR MEI
ModuleC2 (Core Mathematics 2)
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicStationary points and optimisation
TypeFind stationary points coordinates
DifficultyModerate -0.8 This is a straightforward application of basic differentiation and finding stationary points. It requires only polynomial differentiation (power rule), setting the derivative to zero, and solving a simple quadratic. This is a standard textbook exercise with no problem-solving insight required, making it easier than average.
Spec1.07i Differentiate x^n: for rational n and sums1.07n Stationary points: find maxima, minima using derivatives

4 You are given that \(y = x ^ { 3 } - 12 x\).
  1. Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\).
  2. Hence find the coordinates of the turning points of the curve.

AnswerMarks Guidance
(i) \(\frac{dy}{dx} = 3x^2 - 12\)M1, A1 Total: 2 marks
(ii) \(3x^2 - 12 = 0\) when \(x = \pm 2\) \(\Rightarrow (2, -16)\) and \((-2, 16)\)M1, B1, B1 Total: 3 marks
**(i)** $\frac{dy}{dx} = 3x^2 - 12$ | M1, A1 | **Total: 2 marks**

**(ii)** $3x^2 - 12 = 0$ when $x = \pm 2$ $\Rightarrow (2, -16)$ and $(-2, 16)$ | M1, B1, B1 | **Total: 3 marks**
4 You are given that $y = x ^ { 3 } - 12 x$.\\
(i) Find $\frac { \mathrm { d } y } { \mathrm {~d} x }$.\\
(ii) Hence find the coordinates of the turning points of the curve.

\hfill \mbox{\textit{OCR MEI C2  Q4 [5]}}