Find the first 4 terms, in ascending powers of xxx, of the binomial expansion of (1−2x)5(1 - 2x)^5(1−2x)5. Give each term in its simplest form.
If x x\,x is small, so that x2 x^2\,x2 and higher powers can be ignored, show that
(1+x)(1−2x)5≈1−9x. (1 + x)(1 - 2x)^5 \approx 1 - 9x. (1+x)(1−2x)5≈1−9x.10 exam-style questions on Edexcel A Level Old Maths The Binomial Expansion. Each one has a worked solution and a mark scheme showing where the marks go.