Find the first four terms, in ascending powers of xxx, of the binomial expansion of 1+2x \sqrt{1 + 2x}\,1+2x giving each term in its simplest form.
Explain how you could use x=18\displaystyle x = \frac{1}{8}x=81 in the expansion to find an approximation for 5\sqrt{5}5. There is no need to carry out the calculation.
408 exam-style questions on Edexcel A Level Maths Binomial Expansion, covering 4.1 Expanding (1 + x)^n, 4.2 Expanding (a + bx)^n, and 4.3 Using Partial Fractions. Each one has a worked solution and a mark scheme showing where the marks go.