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

Numerical solution of equations — practice question

The diagram represents the curve given by the equation $y = \frac{\ln(2x + 1)}{x + 3}$. This curve has a maximum point $M$.
(a)[2]

Find a formula for $\frac{dy}{dx}$.

(b)[2]

Show that the $x$-coordinate of $M$ obeys the equation $x = \frac{x + 3}{\ln(2x + 1)} - 0.5$.

(c)[2]

Show by calculation that the $x$-coordinate of $M$ is between $2.5$ and $3.0$.

(d)[3]

Use an iterative formula based on the equation in part (b) to find the $x$-coordinate of $M$ correct to $4$ significant figures. Give the result of each iteration to $6$ significant figures.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Some attempt to apply the quotient rule

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