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

Numerical solution of equations — practice question

(i)[2]

By drawing a suitable pair of graphs, show that the equation $5e^{-x} = \sqrt{x}$ has one root.

(ii)[2]

Show that, if a sequence of values produced by the iterative formula $x_{n+1} = \frac{1}{2}\ln\left(\frac{25}{x_n}\right)$ converges, then its limit is the root of the equation in part (i).

(iii)[3]

Use this iterative formula, together with initial value $x_1 = 1$, to calculate the root correct to 2 decimal places. Show the result from 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 an appropriate graph

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