OCR MEI C3 — Question 2 4 marks

Exam BoardOCR MEI
ModuleC3 (Core Mathematics 3)
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicIndefinite & Definite Integrals
TypeExponential and logarithmic integration
DifficultyModerate -0.8 This is a straightforward two-part question requiring basic algebraic expansion followed by routine integration of exponential functions. Part (i) is simple algebra, and part (ii) follows directly from the expansion with no problem-solving needed—just applying standard integration rules for e^x terms.
Spec1.06a Exponential function: a^x and e^x graphs and properties1.08c Integrate e^(kx), 1/x, sin(kx), cos(kx)

  1. Expand \((e^x + e^{-x})^2\). [1]
  2. Hence find \(\int (e^x + e^{-x})^2 dx\). [3]

(i)
AnswerMarks Guidance
\(e^{2x} + 2 + e^{-2x}\)B1 1 mark
(ii)
AnswerMarks Guidance
\(\int(e^{2x} + 2 + e^{-2x})dx = \frac{1}{2}e^{2x} + 2x - \frac{1}{2}e^{-2x} + c\)B1, B1, B1 One for each exponential term, one for both \(2x\) and constant. 3 marks
### (i)
$e^{2x} + 2 + e^{-2x}$ | B1 | 1 mark

### (ii)
$\int(e^{2x} + 2 + e^{-2x})dx = \frac{1}{2}e^{2x} + 2x - \frac{1}{2}e^{-2x} + c$ | B1, B1, B1 | One for each exponential term, one for both $2x$ and constant. 3 marks

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\begin{enumerate}[label=(\roman*)]
\item Expand $(e^x + e^{-x})^2$. [1]
\item Hence find $\int (e^x + e^{-x})^2 dx$. [3]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI C3  Q2 [4]}}