Mathematics 9709 · AS & A Level · Numerical solution of equations

Numerical solution of equations — practice question

The curve defined by $y = x^2 \cos\left(\tfrac{1}{2}x\right)$ possesses a stationary point at $x = p$ for values of $x$ in the range $0 < x < \pi$.
(a(i))[3]

Show that $p$ meets the equation $\tan\left(\tfrac{1}{2}p\right) = \frac{4}{p}$.

(a(ii))[2]

Use calculations to confirm that $p$ is between $2$ and $2.5$.

(a(iii))[3]

Apply the iterative formula $p_{n+1} = 2\tan^{-1}\left(\frac{4}{p_n}\right)$ to find $p$ correct to 2 decimal places. Record every iteration to 4 decimal places.

Worked solution & mark scheme

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