Expand (4−5x)12\displaystyle (4 - 5x)^{\frac{1}{2}}(4−5x)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 3.5 \sqrt{3.5}\,3.5 correct to 5 significant figures.
67 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.