OCR C3 2014 June — Question 3 6 marks

Exam BoardOCR
ModuleC3 (Core Mathematics 3)
Year2014
SessionJune
Marks6
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicAreas by integration
TypeDeduce related integral from numerical approximation
DifficultyModerate -0.3 Part (i) is a standard Simpson's rule application with straightforward function evaluation. Part (ii) requires recognizing that the integral can be split using linearity, with the first term integrating trivially to 2 and the second being 10 times the result from (i). This is routine manipulation once Simpson's rule is applied, requiring only basic integral properties rather than novel insight.
Spec1.09f Trapezium rule: numerical integration

3
  1. Use Simpson's rule with four strips to find an approximation to $$\int _ { 0 } ^ { 2 } \mathrm { e } ^ { \sqrt { x } } \mathrm {~d} x$$ giving your answer correct to 3 significant figures.
  2. Deduce an approximation to \(\int _ { 0 } ^ { 2 } \left( 1 + 10 \mathrm { e } ^ { \sqrt { x } } \right) \mathrm { d } x\).

Question 3(i):
AnswerMarks Guidance
AnswerMarks Guidance
Attempt calculation \(k(y + 4y + 2y + \ldots)\)M1 any constant \(k\); using \(y\) values with coefficients 1, 2, 4 each occurring at least once; brackets may be implied by subsequent calculation. Allow M1 for attempt using \(y\) values based on wrong \(x\) values such as 0, 1, 2, 3, 4; attempt based on \(k(y_0 + y_4) + 4y_1 + 2y_2 + 4y_3\) is M0 unless subsequent calculation shows missing brackets are 'present'
Obtain \(k(e^0 + 4e^{\sqrt{0.5}} + 2e + 4e^{\sqrt{1.5}} + e^{\sqrt{2}})\)A1 or equiv perhaps involving decimal values \(1, 2.02811\ldots, 2.71828\ldots, 3.40329\ldots, 4.11325\ldots\)
Use \(k = \frac{1}{2} \times \frac{1}{2}\)A1
Obtain \(5.38\)A1 allow \(5.379\) but not, in final answer, greater 'accuracy'; answer \(5.38 + c\) is final A0. Answer only: 0/4
Total[4]
Question 3(ii):
AnswerMarks Guidance
AnswerMarks Guidance
Attempt calculation of form \(10 \times (\text{answer to part i}) + k\)M1 implied by correct answer only or by answer following correctly from their incorrect part (i); any non-zero constant \(k\). Allow attempt involving second use of Simpson's rule: M1 for complete correct expression, A1 for answer
Obtain \(55.8\) or greater accuracy based on their part (i) – more than 3 s.f. acceptableA1ft following their answer to part (i) but A0 for \(55.8 + c\). Answer only \(54.8\) with no working earns M1A0 (as does \(10(\text{their ans}) + 1\)); otherwise incorrect answer with no working earns 0/2
Total[2]
## Question 3(i):

| Answer | Marks | Guidance |
|--------|-------|----------|
| Attempt calculation $k(y + 4y + 2y + \ldots)$ | M1 | any constant $k$; using $y$ values with coefficients 1, 2, 4 each occurring at least once; brackets may be implied by subsequent calculation. Allow M1 for attempt using $y$ values based on wrong $x$ values such as 0, 1, 2, 3, 4; attempt based on $k(y_0 + y_4) + 4y_1 + 2y_2 + 4y_3$ is M0 unless subsequent calculation shows missing brackets are 'present' |
| Obtain $k(e^0 + 4e^{\sqrt{0.5}} + 2e + 4e^{\sqrt{1.5}} + e^{\sqrt{2}})$ | A1 | or equiv perhaps involving decimal values $1, 2.02811\ldots, 2.71828\ldots, 3.40329\ldots, 4.11325\ldots$ |
| Use $k = \frac{1}{2} \times \frac{1}{2}$ | A1 | |
| Obtain $5.38$ | A1 | allow $5.379$ but not, in final answer, greater 'accuracy'; answer $5.38 + c$ is final A0. Answer only: 0/4 |
| **Total** | **[4]** | |

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## Question 3(ii):

| Answer | Marks | Guidance |
|--------|-------|----------|
| Attempt calculation of form $10 \times (\text{answer to part i}) + k$ | M1 | implied by correct answer only or by answer following correctly from their incorrect part (i); any non-zero constant $k$. Allow attempt involving second use of Simpson's rule: M1 for complete correct expression, A1 for answer |
| Obtain $55.8$ or greater accuracy based on their part (i) – more than 3 s.f. acceptable | A1ft | following their answer to part (i) but A0 for $55.8 + c$. Answer only $54.8$ with no working earns M1A0 (as does $10(\text{their ans}) + 1$); otherwise incorrect answer with no working earns 0/2 |
| **Total** | **[2]** | |

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3 (i) Use Simpson's rule with four strips to find an approximation to

$$\int _ { 0 } ^ { 2 } \mathrm { e } ^ { \sqrt { x } } \mathrm {~d} x$$

giving your answer correct to 3 significant figures.\\
(ii) Deduce an approximation to $\int _ { 0 } ^ { 2 } \left( 1 + 10 \mathrm { e } ^ { \sqrt { x } } \right) \mathrm { d } x$.

\hfill \mbox{\textit{OCR C3 2014 Q3 [6]}}