Mathematics 9709 · AS & A Level · Differentiation

Differentiation — practice question

A curve satisfies $\frac{dy}{dx} = \frac{2}{\sqrt{x}} - 1$ and $P(9, 5)$ lies on the curve.
(i)[4]

Find the equation of the curve.

(ii)[3]

Find the coordinates of the stationary point on the curve.

(iii)[2]

Find an expression for $\frac{d^2 y}{dx^2}$ and determine the nature of the stationary point.

(iv)[2]

The normal to the curve at $P$ makes an angle of $\tan^{-1} k$ with the positive $x$-axis. Find the value of $k$.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Correct integration leading to $y=4\sqrt{x}-x+c$

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