Edexcel C4 2013 June — Question 2

Exam BoardEdexcel
ModuleC4 (Core Mathematics 4)
Year2013
SessionJune
TopicGeneralised Binomial Theorem
TypeDirect quotient expansion

  1. Use the binomial expansion to show that $$\left. \sqrt { ( } \frac { 1 + x } { 1 - x } \right) \approx 1 + x + \frac { 1 } { 2 } x ^ { 2 } , \quad | x | < 1$$
  2. Substitute \(x = \frac { 1 } { 26 }\) into $$\sqrt { \left( \frac { 1 + x } { 1 - x } \right) = 1 + x + \frac { 1 } { 2 } x ^ { 2 } }$$ to obtain an approximation to \(\sqrt { } 3\)
    Give your answer in the form \(\frac { a } { b }\) where \(a\) and \(b\) are integers.