OCR C3 2006 January — Question 3 6 marks

Exam BoardOCR
ModuleC3 (Core Mathematics 3)
Year2006
SessionJanuary
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProduct & Quotient Rules
TypeFind gradient at point
DifficultyModerate -0.3 This is a straightforward application of product rule (part a) and quotient rule (part b) with no algebraic complications. Both parts are standard textbook exercises requiring direct application of differentiation rules with minimal simplification, making it slightly easier than average for A-level.
Spec1.07k Differentiate trig: sin(kx), cos(kx), tan(kx)1.07q Product and quotient rules: differentiation

3
  1. Differentiate \(x ^ { 2 } ( x + 1 ) ^ { 6 }\) with respect to \(x\).
  2. Find the gradient of the curve \(y = \frac { x ^ { 2 } + 3 } { x ^ { 2 } - 3 }\) at the point where \(x = 1\).

Question 3(a):
AnswerMarks Guidance
Answer/WorkingMark Guidance
Attempt use of product ruleM1 Involving \(\ldots + \ldots\)
Obtain \(2x(x+1)^6 \ldots\)A1
Obtain \(\ldots + 6x^2(x+1)^5\)A1 3 Or equivs; ignore subsequent attempt at simplification
Question 3(b):
AnswerMarks Guidance
Answer/WorkingMark Guidance
Attempt use of quotient ruleM1 Or, with adjustment, product rule; allow \(u/v\) confusion
Obtain \(\dfrac{(x^2-3)2x-(x^2+3)2x}{(x^2-3)^2}\)A1 Or equiv
Obtain \(-3\)A1 3 From correct derivative only
## Question 3(a):

| Answer/Working | Mark | Guidance |
|---|---|---|
| Attempt use of product rule | M1 | Involving $\ldots + \ldots$ |
| Obtain $2x(x+1)^6 \ldots$ | A1 | |
| Obtain $\ldots + 6x^2(x+1)^5$ | A1 | **3** Or equivs; ignore subsequent attempt at simplification |

## Question 3(b):

| Answer/Working | Mark | Guidance |
|---|---|---|
| Attempt use of quotient rule | M1 | Or, with adjustment, product rule; allow $u/v$ confusion |
| Obtain $\dfrac{(x^2-3)2x-(x^2+3)2x}{(x^2-3)^2}$ | A1 | Or equiv |
| Obtain $-3$ | A1 | **3** From correct derivative only |

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3
\begin{enumerate}[label=(\alph*)]
\item Differentiate $x ^ { 2 } ( x + 1 ) ^ { 6 }$ with respect to $x$.
\item Find the gradient of the curve $y = \frac { x ^ { 2 } + 3 } { x ^ { 2 } - 3 }$ at the point where $x = 1$.
\end{enumerate}

\hfill \mbox{\textit{OCR C3 2006 Q3 [6]}}