Show that, for n > 0,

$\displaystyle \sum_{i=0}^{n}(-1)^i\binom{n}{i} = 0$

I know i am supposed to use the binomial theorem which is just,

$\displaystyle (a+b)^n = \sum_{i=0}^{n}\binom{n}{i} a^i b^{n-i}$

I am really just not sure where to start though :(

Thank you for any help/tips :)

(if this needs to be moved to Discrete Mathematics, Set Theory and Logic, would a mod please move it. thank you)