CAIE P3 2013 June — Question 2

Exam BoardCAIE
ModuleP3 (Pure Mathematics 3)
Year2013
SessionJune
TopicNewton-Raphson method
TypeExact value from iterative result

2 The sequence of values given by the iterative formula $$x _ { n + 1 } = \frac { x _ { n } \left( x _ { n } ^ { 3 } + 100 \right) } { 2 \left( x _ { n } ^ { 3 } + 25 \right) }$$ with initial value \(x _ { 1 } = 3.5\), converges to \(\alpha\).
  1. Use this formula to calculate \(\alpha\) correct to 4 decimal places, showing the result of each iteration to 6 decimal places.
  2. State an equation satisfied by \(\alpha\) and hence find the exact value of \(\alpha\).