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

Numerical solution of equations — practice question

For the curve defined by $y = 5e^{2x} - 8x^2 - 20$, there is only one point where it intersects the $x$-axis. The coordinates of this point are $(p, 0)$.
(i)[2]

Show that the value $p$ satisfies the equation $x = \frac{1}{2}\ln(1.6x^2 + 4)$.

(ii)[2]

Show by calculation that $0.75 \le p \le 0.85$.

(iii)[3]

Use the iterative method based on the equation in part (i) to determine the value of $p$ correct to 5 significant figures. Record the outcome of each iteration to 7 significant figures.

(iv)[3]

Find the gradient of the curve at the point $(p, 0)$, using the point given.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Rearrange the equation to at least the stage $2x=\ln(\ldots)$

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