An arithmetic sequence has first term a a\,a and common difference ddd. The sum of the first 25 terms of the sequence is equal to the square of the sum of the first 10 terms.
Show that 4a2+36ad+81d2=a+12d4a^2 + 36ad + 81d^2 = a + 12d4a2+36ad+81d2=a+12d.
Given that the 10th term of the sequence is 2, find the possible values of aaa.
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.