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

Numerical solution of equations — practice question

We are told that $\int_0^a x\cos x\,dx = 0.5$, with $0 < a < \frac{1}{2}\pi$.
(i)[4]

Hence demonstrate that $a$ satisfies $\sin a = \frac{1.5 - \cos a}{a}$.

(ii)[2]

Confirm by calculation that $a$ is greater than $1$.

(iii)[3]

Apply the iterative formula $a_{n+1} = \sin^{-1}\left(\frac{1.5 - \cos a_n}{a_n}\right)$ to find $a$ correct to $4$ decimal places, giving each iteration to $6$ decimal places.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Carry out the integration and arrive at $x\sin x+\int\sin x\,dx$

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