CAIE P1 2016 November — Question 1 4 marks

Exam BoardCAIE
ModuleP1 (Pure Mathematics 1)
Year2016
SessionNovember
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicIntegration by Substitution
TypeFinding curve equation from derivative
DifficultyModerate -0.8 This is a straightforward integration problem requiring a simple substitution (u = 4x + 1) to integrate (4x + 1)^(-1/2), followed by using the given point to find the constant of integration. It's a standard textbook exercise with clear steps and no conceptual challenges, making it easier than average for A-level.
Spec1.08b Integrate x^n: where n != -1 and sums

1 A curve is such that \(\frac { \mathrm { d } y } { \mathrm {~d} x } = \frac { 8 } { \sqrt { } ( 4 x + 1 ) }\). The point \(( 2,5 )\) lies on the curve. Find the equation of the curve.

Question 1:
AnswerMarks Guidance
Answer/WorkingMarks Guidance
\((y) = 8(4x+1)^{\frac{1}{2}} \div \frac{1}{2} \div 4 \, (+c)\)B1 Correct integrand (unsimplified) without \(\div 4\)
B1\(\div 4\). Ignore \(c\)
Uses \(x = 2\) and \(y = 5\)M1 Substitution of correct values into an integrand to find \(c\)
\(c = -7\)A1 \(y = 4\sqrt{4x+1} - 7\)
## Question 1:

| Answer/Working | Marks | Guidance |
|---|---|---|
| $(y) = 8(4x+1)^{\frac{1}{2}} \div \frac{1}{2} \div 4 \, (+c)$ | B1 | Correct integrand (unsimplified) without $\div 4$ |
| | B1 | $\div 4$. Ignore $c$ |
| Uses $x = 2$ and $y = 5$ | M1 | Substitution of correct values into an integrand to find $c$ |
| $c = -7$ | A1 | $y = 4\sqrt{4x+1} - 7$ |

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1 A curve is such that $\frac { \mathrm { d } y } { \mathrm {~d} x } = \frac { 8 } { \sqrt { } ( 4 x + 1 ) }$. The point $( 2,5 )$ lies on the curve. Find the equation of the curve.

\hfill \mbox{\textit{CAIE P1 2016 Q1 [4]}}