A geometric series has a second term of 3 and its sum to infinity is 16.
Determine the two possible values of rrr.
Determine the corresponding two possible values of aaa.
Given that r r\,r takes the larger of the two possible values, find the smallest value of n n\,n for which Sn>15.5S_n > 15.5Sn>15.5.
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.