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. Part (i) requires only routine polynomial differentiation using the power rule, and part (ii) involves setting the derivative equal to zero and solving a simple quadratic equation. Both steps are standard textbook exercises 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
  1. Differentiate \(x ^ { 3 } - 6 x ^ { 2 } - 15 x + 50\).
  2. Hence find the \(x\)-coordinates of the stationary points on the curve \(y = x ^ { 3 } - 6 x ^ { 2 } - 15 x + 50\).

Question 4:
Part (i):
AnswerMarks Guidance
AnswerMarks Guidance
\(3x^2 - 12x - 15\)2 M1 if one term incorrect or an extra term is included
Part (ii):
AnswerMarks Guidance
AnswerMarks Guidance
Their \(\frac{dy}{dx} = 0\) s.o.i.M1
\(x = 5\)B1
\(x = -1\)B1
## Question 4:

### Part (i):

| Answer | Marks | Guidance |
|--------|-------|----------|
| $3x^2 - 12x - 15$ | **2** | **M1** if one term incorrect or an extra term is included |

---

### Part (ii):

| Answer | Marks | Guidance |
|--------|-------|----------|
| Their $\frac{dy}{dx} = 0$ s.o.i. | **M1** | |
| $x = 5$ | **B1** | |
| $x = -1$ | **B1** | |

---
4 (i) Differentiate $x ^ { 3 } - 6 x ^ { 2 } - 15 x + 50$.\\
(ii) Hence find the $x$-coordinates of the stationary points on the curve $y = x ^ { 3 } - 6 x ^ { 2 } - 15 x + 50$.

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