Find the first 4 terms, in ascending powers of xxx, of the binomial expansion of (1+ax)10(1 + ax)^{10}(1+ax)10, where a a\,a is a non-zero constant. Give each term in its simplest form.
Given that, in this expansion, the coefficient of x3 x^3\,x3 is double the coefficient of x2x^2x2, find the value of aaa.
Practise Edexcel A Level Old Maths The Binomial Expansion with exam-style questions for A Level Old Maths. 10 questions, matched to the Edexcel A Level Old Maths (9371) specification and written in Unit exams C1, C2, C3 and C4 plus two applied units (e.g. S1 and M1) 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.