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

Numerical solution of equations — practice question

The constant $a$ is defined by $\int_{0}^{a} x e^{-2x}\, dx = \frac{1}{8}$.
(a)[5]

Demonstrate that $a = \frac{1}{2} \ln(4a + 2)$.

(b)[2]

Confirm by calculation that $a$ lies between $0.5$ and $1$.

(c)[3]

Apply the iterative formula arising from the equation in (a) to find $a$ correct to 2 decimal places. Record every iterate to 4 decimal places.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Begin the integration properly and reach $pxe^{-2x}+q\int e^{-2x}\,dx$.

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