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1.7 D: Sequences and series

1.7 D: Sequences and series

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Question 209
a.

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

(3−13x)5 \left(3 - \frac{1}{3}x\right)^5 (3−31​x)5
[4]
b.

Given that xxx is small, so terms in x4x^4x4 and higher powers of xxx may be ignored, show

(3−13x)5+(3+13x)5=a+bx2 \left(3 - \frac{1}{3}x\right)^5 + \left(3 + \frac{1}{3}x\right)^5 = a + bx^2 (3−31​x)5+(3+31​x)5=a+bx2

where aaa and bbb are constants to be found.

[3]
Markscheme

1.7 D: Sequences and series Questions

  1. A Level
  2. /Maths
  3. /1.7 D: Sequences and series

308 exam-style questions on AQA A Level Maths 1.7 D: Sequences and series, covering 1.7.1 Binomial expansion, 1.7.2 Types of sequence (A-level only), 1.7.3 Sigma notation (A-level only), 1.7.4 Arithmetic sequences and series (A-level only), 1.7.5 Geometric sequences and series (A-level only), and 1.7.6 Sequences and series in modelling (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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