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Binomial Expansion

Binomial Expansion

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Question 233
a.

The first four terms, in ascending powers of xxx, of the binomial expansion of 1+ax \sqrt{1 + ax}\,1+ax​ are

1+3x−92x2+272x3.1 + 3x - \frac{9}{2}x^2 + \frac{27}{2}x^3.1+3x−29​x2+227​x3.

Find the value of aaa.

[3]
b.

Explain how you could use the expansion to find an approximation for 6\sqrt{6}6​. State the value of x x\,x that should be used. There is no need to carry out the calculation.

[2]
Markscheme

Binomial Expansion Questions

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

409 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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