Expand (9−2x)12\displaystyle (9 - 2x)^{\frac{1}{2}}(9−2x)21 in ascending powers of x x\,x up to and including the term in x3x^3x3.
Write down the range of values of x x\,x for which the expansion is valid.
Use your expansion, with a suitable value of xxx, to find the value of 8.9 \sqrt{8.9}\,8.9 correct to five significant figures. State the value of x x\,x that you use.
36 exam-style questions on CCEA A Level Maths 3.3.7 Sequences and series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.