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

Numerical solution of equations — practice question

(i)[2]

By sketching a suitable pair of graphs, show that the equation $\cot x = 1 + x^2$, with $x$ measured in radians, has a single root for $0 < x < \frac{1}{2}\pi$.

(ii)[2]

Verify by calculation that this root is located between $0.5$ and $0.8$.

(iii)[3]

Use the iterative formula $x_{n+1} = \tan^{-1}\left(\frac{1}{1 + x_n^2}\right)$ to find this root correct to $2$ decimal places. Record each iteration to $4$ decimal places.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: Produce a recognisable sketch of the appropriate graph across the stated range

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