Given that kkk is a constant and the binomial expansion of 1+kx,∣kx∣<1\sqrt{1 + kx}, \quad |kx| < 11+kx,∣kx∣<1 in ascending powers of xxx up to the term in x3x^3x3 is 1+14x+Ax2+Bx31 + \frac{1}{4}x + Ax^2 + Bx^31+41x+Ax2+Bx3
(i) find the value of kkk,
(ii) find the value of the constant AAA and the constant BBB.
Use the expansion to find an approximate value to 1.2\sqrt{1.2}1.2.
Show your working and give your answer to 6 decimal places.
Practise Edexcel A Level Maths 4.1 Expanding (1 + x)^n with exam-style questions for A Level Maths. 12 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.