A geometric series is a+ar+ar2+…a + ar + ar^2 + \dotsa+ar+ar2+…
Prove that the sum of the first n n\,n terms of the series is
Sn=a(1−rn)1−r S_n = \frac{a(1-r^n)}{1-r} Sn=1−ra(1−rn)Practise AQA A Level Maths 1.7 D: Sequences and series with exam-style questions for A Level Maths. 267 questions 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), matched to the AQA A Level Maths (7357) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.