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Binomial Expansion

Binomial Expansion

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Question 225
a.

The expansion of (a−bx)12\displaystyle (a-bx)^{\frac{1}{2}}(a−bx)21​ in ascending powers of x x\,x up to and including x3 x^3\,x3 is

3−13x−154x2−1486x3 3 - \frac{1}{3}x - \frac{1}{54}x^2 - \frac{1}{486}x^3 3−31​x−541​x2−4861​x3

Find the values of a a\,a and bbb

[4]
b.

Write down the range of values of x x\,x for which the expansion is valid.

[1]
c.

Use your expansion, with a suitable value of xxx, to find the value of 8.9 \sqrt{8.9}\,8.9​ correct to 5 significant figures

[2]
Markscheme

Binomial Expansion Questions

  1. A Level
  2. /Maths
  3. /Binomial Expansion

408 exam-style questions on Edexcel A Level Maths Binomial Expansion, covering 4.1 Expanding (1 + x)^n, 4.2 Expanding (a + bx)^n, and 4.3 Using Partial Fractions. Each one has a worked solution and a mark scheme showing where the marks go.

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