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CAPE Pure Mathematics Unit 2 · May/June 2010 · Paper 2 · Question 3(c)(ii)

Prove that \frac{x}{1 + x + \sqrt{1 + 2x}} = \frac{1}{x}(1 + x - \sqrt{1 + 2x}) for x > 0.

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Other parts of this question

  1. 3(a)(i)Express, in terms of r, the r^{\text{th}} term of the sequence.[2 marks]
  2. 3(a)(ii)If S_n denotes the series formed by summing the first n terms of the sequence, find S_n in terms of n.[5 marks]
  3. 3(b)The 9^{\text{th}} term of an A.P. is three times the 3^{\text{rd}} term and the sum of the first 10 terms is 110. Find the first term a and the common…[6 marks]
  4. 3(c)(i)Use the binomial theorem to expand (1 + 2x)^{\frac{1}{2}} as far as the term in x^3, stating the values of x for which the expansion is valid.[5 marks]
  5. 3(c)(iii)Hence, or otherwise, show that, if x is small so that the term in x^3 and higher powers of x can be neglected, the expansion in (c)(ii) above is…[3 marks]

More practice: the rest of this paper · more The Binomial Theorem questions · all CAPE Pure Mathematics Unit 2 past papers