Expand (3+2x)12\displaystyle (3+2x)^{\frac{1}{2}}(3+2x)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.
Use your expansion, with x=0.1x=0.1x=0.1, to find an approximation of the value of 5 \sqrt{5}\,5 Give your answer to 3 decimal places.