Chapter 4 Binomial Expansion (Year 2)

Question 1

How do you expand (1 + x)^n if n is a fraction/negative number?

Answer 1

Use the special form of the binomial expansion (given in the formula book)

Question 2

For what range is the expansion of (1 + bx)^n valid for? (n is negative or a fraction)

Answer 2

For |x|<1/b

Question 3

How do you expand (a + bx)^n when n is negative or a fraction?

Answer 3

Take a factor of a^n out of the expression:
(a + bx)^n = a^n(1 + b/a x)^n

Question 4

When is the expansion of (a + bx)^n when n is negative or a fraction valid?

Answer 4

When |x|<a/b