Edexcel F1 2014 June — Question 4

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2014
SessionJune
TopicNewton-Raphson method
TypeCompare Newton-Raphson with linear interpolation

4. $$\mathrm { f } ( x ) = x ^ { \frac { 3 } { 2 } } - 3 x ^ { \frac { 1 } { 2 } } - 3 , \quad x > 0$$ Given that \(\alpha\) is the only real root of the equation \(\mathrm { f } ( x ) = 0\),
  1. show that \(4 < \alpha < 5\)
  2. Taking 4.5 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 decimal places.
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  3. Use linear interpolation once on the interval [4,5] to find another approximation to \(\alpha\), giving your answer to 3 decimal places.