Edexcel F1 2021 October — Question 2

Exam BoardEdexcel
ModuleF1 (Further Pure Mathematics 1)
Year2021
SessionOctober
TopicSign Change & Interval Methods
TypeNewton-Raphson with Other Methods

2. $$f ( x ) = 7 \sqrt { x } - \frac { 1 } { 2 } x ^ { 3 } - \frac { 5 } { 3 x } \quad x > 0$$
  1. Show that the equation \(\mathrm { f } ( x ) = 0\) has a root, \(\alpha\), in the interval [2.8, 2.9]
    1. Find \(\mathrm { f } ^ { \prime } ( x )\).
    2. Hence, using \(x _ { 0 } = 2.8\) as a first approximation to \(\alpha\), apply the Newton-Raphson procedure once to \(\mathrm { f } ( x )\) to calculate a second approximation to \(\alpha\), giving your answer to 3 decimal places.
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  2. Use linear interpolation once on the interval [2.8, 2.9] to find another approximation to \(\alpha\). Give your answer to 3 decimal places.
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