A-level · Numerical methods

The Newton–Raphson methodExam-style questions

A fast iteration that uses the tangent — x_(n+1) = x_n − f(x_n)/f'(x_n) — its geometric meaning, why it converges so quickly, and the cases where it fails (a horizontal tangent or a poor starting value).

23 questions · A-level level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3Level 4Level 5
  1. 1
    f(x)=x3−2x−5f(x) = x^3 - 2x - 5. Using the Newton–Raphson method with x0=2x_0 = 2, find x1x_1.
    Level 2 · 2 marksTry it
  2. 2
    The positive root of x2−7=0x^2 - 7 = 0 is 7\sqrt7. Using Newton–Raphson with x0=3x_0 = 3, find x1x_1 and x2x_2 to 4 decimal places.
    Level 2 · 3 marksTry it