Edexcel FP1 2013 January — Question 3

Exam BoardEdexcel
ModuleFP1 (Further Pure Mathematics 1)
Year2013
SessionJanuary
TopicNewton-Raphson method
TypeNewton-Raphson with complex derivative required

3. $$\mathrm { f } ( x ) = 2 x ^ { \frac { 1 } { 2 } } + x ^ { - \frac { 1 } { 2 } } - 5 , \quad x > 0$$
  1. Find \(\mathrm { f } ^ { \prime } ( x )\). The equation \(\mathrm { f } ( x ) = 0\) has a root \(\alpha\) in the interval [4.5, 5.5].
  2. Using \(x _ { 0 } = 5\) as a first approximation to \(\alpha\), apply the Newton-Raphson procedure once to \(\mathrm { f } ( x )\) to find a second approximation to \(\alpha\), giving your answer to 3 significant figures.