Binomial theorem

• The general term: there are n+1 terms in the expansion of $(a+b{)}^2$
  • general way to describe any term: ${(}^n{C}_k)a^{n-k}{b}^k$

Pascals triangle

• gives binomial coefficients (i.e. the coefficient of the ${}^n{C}_k$ term, not including expansion of other terms)
• the nth row gives the coefficient of the expansion of $(1+x{)}^n$