A quantitative analyst models the projected value of a portfolio using the function
V(x)=(4+kx)7V(x) = (4 + kx)^7V(x)=(4+kx)7
where x x\,x represents market volatility and k k\,k is a positive constant.
Find the first three terms, in ascending powers of xxx, in the expansion of (4+kx)7(4 + kx)^7(4+kx)7, giving each term in its simplest form.
Given that the coefficient of x2 x^2\,x2 is exactly three-eighths of the coefficient of xxx, determine the value of kkk.
144 exam-style questions on AQA A Level Maths 1.7.1 Binomial expansion. Each one has a worked solution and a mark scheme showing where the marks go.