Edexcel C4 — Question 2

Exam BoardEdexcel
ModuleC4 (Core Mathematics 4)
TopicGeneralised Binomial Theorem
TypeDirect single expansion substitution

2. $$f ( x ) = \frac { 3 } { \sqrt { 1 - x } } , | x | < 1$$
  1. Show that \(\mathrm { f } \left( \frac { 1 } { 10 } \right) = \sqrt { 10 }\).
  2. Expand \(\mathrm { f } ( x )\) in ascending powers of \(x\) up to and including the term in \(x ^ { 3 }\), simplifying each coefficient.
  3. Use your expansion to find an approximate value for \(\sqrt { 10 }\), giving your answer to 8 significant figures.
  4. Find, to 1 significant figure, the percentage error in your answer to part (c).