OCR C3 — Question 7 10 marks

Exam BoardOCR
ModuleC3 (Core Mathematics 3)
Marks10
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicAreas by integration
TypeArea between curve and line
DifficultyModerate -0.3 Part (a) is a routine integration using substitution or recognition of a standard form, requiring only mechanical application of techniques. Part (b) involves setting up an area calculation with definite integration of 1/x and algebraic manipulation to reach the given answer, but follows a standard template for such problems. Both parts are slightly easier than average C3 questions due to their straightforward nature, though part (b) requires careful setup and simplification.
Spec1.08d Evaluate definite integrals: between limits1.08e Area between curve and x-axis: using definite integrals1.08h Integration by substitution

  1. Find the exact value of \(\int_1^2 \frac{2}{(4x - 1)^2} \, dx\). [4]
  2. \includegraphics{figure_7b} The diagram shows part of the curve \(y = \frac{1}{x}\). The point \(P\) has coordinates \((a, \frac{1}{a})\) and the point \(Q\) has coordinates \((2a, \frac{1}{2a})\), where \(a\) is a positive constant. The point \(R\) is such that \(PR\) is parallel to the \(x\)-axis and \(QR\) is parallel to the \(y\)-axis. The region shaded in the diagram is bounded by the curve and by the lines \(PR\) and \(QR\). Show that the area of this shaded region is \(\ln(\frac{4}{e})\). [6]

\begin{enumerate}[label=(\alph*)]
\item Find the exact value of $\int_1^2 \frac{2}{(4x - 1)^2} \, dx$. [4]

\item \includegraphics{figure_7b}

The diagram shows part of the curve $y = \frac{1}{x}$. The point $P$ has coordinates $(a, \frac{1}{a})$ and the point $Q$ has coordinates $(2a, \frac{1}{2a})$, where $a$ is a positive constant. The point $R$ is such that $PR$ is parallel to the $x$-axis and $QR$ is parallel to the $y$-axis. The region shaded in the diagram is bounded by the curve and by the lines $PR$ and $QR$. Show that the area of this shaded region is $\ln(\frac{4}{e})$. [6]
\end{enumerate}

\hfill \mbox{\textit{OCR C3  Q7 [10]}}