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

Numerical solution of equations — practice question

The figure displays the curve $y = 3e^{2x-1}$. The shaded area is enclosed by the curve together with the lines $x = a$, $x = a + 1$ and $y = 0$, where $a$ is a constant. The area of this shaded region is given as $120$ square units.
(a)[5]

Show, by manipulation, that $a = \frac{1}{2}\ln(80 + e^{2a-1}) - \frac{1}{2}$.

(b)[3]

Use an iterative formula, taken from the equation in part (a), to determine the value of $a$ correct to $3$ significant figures. Record the result of every iteration to $5$ significant figures.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Integrate so that the result is written in the form $ke^{2x-1}$

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