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

Numerical solution of equations — practice question

A curve has equation $y = x \ln(8 - x)$. Its gradient is 1 at exactly one point, where $x = a$.
(i)[3]

Show that $a$ satisfies $x = 8 - \frac{8}{\ln(8 - x)}$.

(ii)[2]

Use calculation to confirm that $a$ lies between $2.9$ and $3.1$.

(iii)[3]

Use an iterative formula derived from the equation in part (i) to find $a$ correct to 2 decimal places. State each iterate to 4 decimal places.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Apply the product rule to a valid expression.

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