Find the first three terms, in ascending powers of xxx, in the expansion of (3+kx)4(3 + kx)^4(3+kx)4 where k k\,k is a positive constant.
Hence, given that the coefficient of x x\,x is four times the coefficient of x2x^2x2, find the value of kkk.
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.