In this question you should assume that −12<x<12\displaystyle -\frac{1}{2} < x < \frac{1}{2}−21<x<21.
For the binomial expansion of (1−2x)−2(1 - 2x)^{-2}(1−2x)−2, find and simplify the first four terms.
Write down the sum to infinity of the series 1+2x+4x2+8x3+…1 + 2x + 4x^2 + 8x^3 + \dots1+2x+4x2+8x3+…
Hence, or otherwise, find and simplify an expression for 2+6x+16x2+40x3+…2 + 6x + 16x^2 + 40x^3 + \dots2+6x+16x2+40x3+…
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.