Binomial Expansion

EasyMedium
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Question 61
Medium

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+41​x+Ax2+Bx3

a.

(i) find the value of kkk,

(ii) find the value of the constant AAA and the constant BBB.

[5]
b.

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.

[4]

Binomial Expansion Questions

  1. A Level
  2. /Maths
  3. /Binomial Expansion