Prove that mathematically, Sinx/x=1?

It is not true that sin(x)/x = 1; for example, if x = 2 pi, sin(2 pi) = 0, so sin(2 pi)/2 pi = 0. However, it is true that lim(x -> 0){sin(x)/x} = 1. For a proof, use L'Hospital's Rule.