CAIE FP1 2009 November — Question 1 4 marks

Exam BoardCAIE
ModuleFP1 (Further Pure Mathematics 1)
Year2009
SessionNovember
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProduct & Quotient Rules
TypeFind derivative of product
DifficultyStandard +0.3 This question requires applying the product rule twice and then computing mean values via integration. While it involves multiple steps (differentiation, integration, evaluation), each step is straightforward application of standard techniques. The product rule application is routine, and finding mean values by integration is a standard A-level further maths procedure. The calculations are somewhat lengthy but conceptually straightforward, making it slightly easier than average.
Spec1.07k Differentiate trig: sin(kx), cos(kx), tan(kx)1.08i Integration by parts4.08e Mean value of function: using integral

1 Given that $$y = x ^ { 2 } \sin x$$
  1. show that the mean value of \(\frac { \mathrm { d } y } { \mathrm {~d} x }\) with respect to \(x\) over the interval \(0 \leqslant x \leqslant \frac { 1 } { 2 } \pi\) is \(\frac { 1 } { 2 } \pi\),
  2. find the mean value of \(\frac { \mathrm { d } ^ { 2 } y } { \mathrm {~d} x ^ { 2 } }\) with respect to \(x\) over the interval \(0 \leqslant x \leqslant \frac { 1 } { 2 } \pi\).

AnswerMarks
(i) \(\text{MV of } y_1 \text{ over } 0 \leq x \leq \pi/2 = 2/\pi [x^3 \sin x]_0^{\pi/2}\)M1
\(= ... = \pi/2\) (AG, CWO)A1
(ii) \(\text{MV of } y_2 \text{ over } 0 \leq x \leq \pi/2 = 2/\pi [2x \sin x + x^2 \cos x]_0^{\pi/2} = 2\)M1A1
(i) $\text{MV of } y_1 \text{ over } 0 \leq x \leq \pi/2 = 2/\pi [x^3 \sin x]_0^{\pi/2}$ | M1 | 
$= ... = \pi/2$ (AG, CWO) | A1 |

(ii) $\text{MV of } y_2 \text{ over } 0 \leq x \leq \pi/2 = 2/\pi [2x \sin x + x^2 \cos x]_0^{\pi/2} = 2$ | M1A1 |
1 Given that

$$y = x ^ { 2 } \sin x$$

(i) show that the mean value of $\frac { \mathrm { d } y } { \mathrm {~d} x }$ with respect to $x$ over the interval $0 \leqslant x \leqslant \frac { 1 } { 2 } \pi$ is $\frac { 1 } { 2 } \pi$,\\
(ii) find the mean value of $\frac { \mathrm { d } ^ { 2 } y } { \mathrm {~d} x ^ { 2 } }$ with respect to $x$ over the interval $0 \leqslant x \leqslant \frac { 1 } { 2 } \pi$.

\hfill \mbox{\textit{CAIE FP1 2009 Q1 [4]}}