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

Numerical solution of equations — practice question

(a)[2]

You are told that $e^{2x} = 5 + \cos 3x$ has just one root. By calculation, show that this root is within $0.7 \le x \le 0.8$.

(b)[1]

Show that any sequence of values in the interval $0.7 \le x \le 0.8$ defined by the iterative formula $x_{n+1} = \frac{1}{2} \ln(5 + \cos 3x_n)$, if it converges, converges to the root of the equation in part (a).

(c)[3]

Use this iterative procedure to find the root correct to 3 decimal places. Include each iteration result to 5 decimal places.

Worked solution & mark scheme

This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: Evaluate the relevant expressions at $x=0.7$ and at $x=0.8$

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI