OCR C3 — Question 5 8 marks

Exam BoardOCR
ModuleC3 (Core Mathematics 3)
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicVolumes of Revolution
TypeRotation about x-axis: rational or reciprocal function
DifficultyModerate -0.8 Part (a) is a straightforward application of the reverse chain rule for integration, requiring only substitution or recognition of a standard form. Part (b) involves the volume of revolution formula with a simple function (1/2√x), requiring integration of x^(-1) which is routine. Both parts are standard textbook exercises with no problem-solving insight needed, making this easier than average for C3.
Spec1.08h Integration by substitution4.08d Volumes of revolution: about x and y axes

  1. Find \(\int (3x + 7)^9 \, dx\). [3]
  2. \includegraphics{figure_5b} The diagram shows the curve \(y = \frac{1}{2\sqrt{x}}\). The shaded region is bounded by the curve and the lines \(x = 3\), \(x = 6\) and \(y = 0\). The shaded region is rotated completely about the \(x\)-axis. Find the exact volume of the solid produced, simplifying your answer. [5]

\begin{enumerate}[label=(\alph*)]
\item Find $\int (3x + 7)^9 \, dx$. [3]

\item \includegraphics{figure_5b}

The diagram shows the curve $y = \frac{1}{2\sqrt{x}}$. The shaded region is bounded by the curve and the lines $x = 3$, $x = 6$ and $y = 0$. The shaded region is rotated completely about the $x$-axis. Find the exact volume of the solid produced, simplifying your answer. [5]
\end{enumerate}

\hfill \mbox{\textit{OCR C3  Q5 [8]}}