Expand (9+18x)−12\displaystyle (9+18x)^{-\frac{1}{2}}(9+18x)−21 in ascending powers of x x\,x up to and including x3x^3x3.
Write down the range of values of x x\,x for which the expansion is valid.
43 exam-style questions on WJEC A Level Maths 3.4.1 Sequences and Series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.