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Binomial Expansion

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Question 35
a.

Find the first three terms, in ascending powers of xxx, of the binomial expansion of

11+x \frac{1}{\sqrt{1+x}} 1+x​1​

giving each coefficient in its simplest form.

[3]
bi.
x=2x=−23x=13 x=2\qquad x=-\frac23\qquad x=\frac13 x=2x=−32​x=31​

Without evaluating your expansion, state, giving a reason, which of the three values of x x\,x should not be used.

[1]
bii.

Without evaluating your expansion, state, giving a reason, which of the three values of x x\,x would lead to the most accurate approximation to 3\sqrt{3}3​

[1]
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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