What is the Binomial Theorem?

The binomial theorem is an algebraic expansion of powers of a polynomial. The coefficients of binomial expansion are termed as binomial coefficients. The expression of the theorem is: (a+b)^n = sum [k=0,n] [(n over k)a^(n-k)b^k]. Example: (a+b)^4 = a^4 + 4a^3b + 6a^2b^2 + 4ab^3 + b^4.