OCR C3 — Question 4 7 marks

Exam BoardOCR
ModuleC3 (Core Mathematics 3)
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicParametric differentiation
TypeFind dy/dx expression in terms of parameter
DifficultyModerate -0.3 This is a straightforward chain rule application requiring standard differentiation of power and exponential functions, then using dy/dx = (dy/dt)/(dx/dt). The calculations are routine with no conceptual challenges beyond applying the chain rule formula, making it slightly easier than average for C3.
Spec1.07k Differentiate trig: sin(kx), cos(kx), tan(kx)1.07r Chain rule: dy/dx = dy/du * du/dx and connected rates

  1. Given that \(x = (4t + 9)^{\frac{1}{2}}\) and \(y = 6e^{\frac{2t+1}{4}}\), find expressions for \(\frac{dx}{dt}\) and \(\frac{dy}{dx}\). [4]
  2. Hence find the value of \(\frac{dy}{dt}\) when \(t = 4\), giving your answer correct to 3 significant figures. [3]

\begin{enumerate}[label=(\roman*)]
\item Given that $x = (4t + 9)^{\frac{1}{2}}$ and $y = 6e^{\frac{2t+1}{4}}$, find expressions for $\frac{dx}{dt}$ and $\frac{dy}{dx}$. [4]
\item Hence find the value of $\frac{dy}{dt}$ when $t = 4$, giving your answer correct to 3 significant figures. [3]
\end{enumerate}

\hfill \mbox{\textit{OCR C3  Q4 [7]}}