Expand (25+2x)12\displaystyle (25 + 2x)^{\frac{1}{2}}(25+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 25.2 \sqrt{25.2}\,25.2 correct to 5 significant figures.
Practise Edexcel A Level Maths 4.2 Expanding (a + bx)^n with exam-style questions for A Level Maths. 99 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.