Binomial Expansion

Question 1

Binomial coefficient

Answer 1

nCr = n!/r!(n-r)!

Question 2

Binomial expansion formula, (1+x)^k =

Answer 2

1 + nx + n(n-1)x^2 / 2! + n(n-1)(n-2)x^3 / 3! for mod(x) < 1

Question 3

Binomial expansion formula, (a+bx)^n =

Answer 3

a^n(1+bx/a)^n for mod(bx/a) < 1