AQA C3 2007 June — Question 6 9 marks

Exam BoardAQA
ModuleC3 (Core Mathematics 3)
Year2007
SessionJune
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicIntegration by Parts
TypeIndependent multi-part (different techniques)
DifficultyModerate -0.3 Part (a) is a textbook integration by parts with polynomial×exponential. Parts (b)(i-ii) involve a straightforward substitution u=√x followed by standard logarithm integration. All techniques are routine C3 applications with no problem-solving insight required, making this slightly easier than average but not trivial due to the multi-step nature and exact value requirement.
Spec1.08h Integration by substitution1.08i Integration by parts

6
  1. Use integration by parts to find \(\int x \mathrm { e } ^ { 5 x } \mathrm {~d} x\).
    1. Use the substitution \(u = \sqrt { x }\) to show that $$\int \frac { 1 } { \sqrt { x } ( 1 + \sqrt { x } ) } \mathrm { d } x = \int \frac { 2 } { 1 + u } \mathrm {~d} u$$
    2. Find the exact value of \(\int _ { 1 } ^ { 9 } \frac { 1 } { \sqrt { x } ( 1 + \sqrt { x } ) } \mathrm { d } x\).

6
\begin{enumerate}[label=(\alph*)]
\item Use integration by parts to find $\int x \mathrm { e } ^ { 5 x } \mathrm {~d} x$.
\item \begin{enumerate}[label=(\roman*)]
\item Use the substitution $u = \sqrt { x }$ to show that

$$\int \frac { 1 } { \sqrt { x } ( 1 + \sqrt { x } ) } \mathrm { d } x = \int \frac { 2 } { 1 + u } \mathrm {~d} u$$
\item Find the exact value of $\int _ { 1 } ^ { 9 } \frac { 1 } { \sqrt { x } ( 1 + \sqrt { x } ) } \mathrm { d } x$.
\end{enumerate}\end{enumerate}

\hfill \mbox{\textit{AQA C3 2007 Q6 [9]}}