Mathematics 9709 · AS & A Level · Differentiation

Differentiation — practice question

The curve is described by the parametric equations $x = \tan \theta$, $y = \sin \theta - 2\sin^3 \theta$, for $0 < \theta < \frac{1}{2}\pi$.
(a)[4]

Show that $\frac{dy}{dx} = 6\cos^5\theta - 5\cos^3\theta$.

(b)[5]

Find the equation of the normal to the curve at the point where it meets the $x$-axis. Give your answer in the form $y = mx + c$, where $m$ and $c$ are exact constants.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Try to use the chain rule when differentiating $y$, or when simplifying $y$, together with the product rule

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