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

Numerical solution of equations — practice question

(a)[3]

Using sketches of $y = |5 - 2x|$ and $y = 3 \ln x$ on one diagram, show that the equation $|5 - 2x| = 3 \ln x$ has exactly two roots.

(b)[1]

Demonstrate that the larger root has to satisfy $x = 2.5 + 1.5 \ln x$.

(c)[2]

Show, by calculation, that the larger root is between $4.5$ and $5.0$.

(d)[3]

Apply an iterative formula, based on the equation in part (b), to determine the larger root correct to $3$ significant figures. Give each iterate to $5$ significant figures.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Produce an accurate sketch of $y = |5 - 2x|$

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