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.
99 exam-style questions on CCEA A Level Maths 1.3.1 Sequences and series. Each one has a worked solution and a mark scheme showing where the marks go.