OCR C3 — Question 3 8 marks

Exam BoardOCR
ModuleC3 (Core Mathematics 3)
Marks8
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicDifferentiating Transcendental Functions
TypeFind tangent line equation
DifficultyStandard +0.3 This is a straightforward two-part question requiring standard differentiation of exponential and logarithmic functions, finding a tangent line equation, then basic coordinate geometry to find intercepts and triangle area. All techniques are routine C3 material with no novel insight required, making it slightly easier than average.
Spec1.07j Differentiate exponentials: e^(kx) and a^(kx)1.07l Derivative of ln(x): and related functions1.07m Tangents and normals: gradient and equations1.08e Area between curve and x-axis: using definite integrals

3. The curve \(C\) has the equation \(y = 2 \mathrm { e } ^ { x } - 6 \ln x\) and passes through the point \(P\) with \(x\)-coordinate 1.
  1. Find an equation for the tangent to \(C\) at \(P\). The tangent to \(C\) at \(P\) meets the coordinate axes at the points \(Q\) and \(R\).
  2. Show that the area of triangle \(O Q R\), where \(O\) is the origin, is \(\frac { 9 } { 3 - \mathrm { e } }\).

3. The curve $C$ has the equation $y = 2 \mathrm { e } ^ { x } - 6 \ln x$ and passes through the point $P$ with $x$-coordinate 1.\\
(i) Find an equation for the tangent to $C$ at $P$.

The tangent to $C$ at $P$ meets the coordinate axes at the points $Q$ and $R$.\\
(ii) Show that the area of triangle $O Q R$, where $O$ is the origin, is $\frac { 9 } { 3 - \mathrm { e } }$.\\

\hfill \mbox{\textit{OCR C3  Q3 [8]}}