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Binomial Expansion

Binomial Expansion

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Question 214

In this question you should assume −12<x<12\displaystyle -\frac{1}{2} < x < \frac{1}{2}−21​<x<21​

a.

The first four terms of the binomial expansion of (1+ax)n(1 + ax)^n(1+ax)n are 1+4x+12x2+32x31 + 4x + 12x^2 + 32x^31+4x+12x2+32x3. Find and simplify the values of a a\,a and nnn.

[2]
b.

Write down the series whose sum to infinity is 11−2x\displaystyle \frac{1}{1-2x}1−2x1​.

[1]
c.

Hence or otherwise find and simplify the series whose sum to infinity is 2−2x(1−2x)2\displaystyle \frac{2-2x}{(1-2x)^2}(1−2x)22−2x​.

[3]
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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