The coin tossing is repeated independently until n tails have been seen. Find the moment generating function of the total number of heads.
I know the number of tosses before the first head is p(X=x)=(1-p)p^x x=0,1,2,...
I know that the moment generating function is found by E(e^tx)
I'm not quite sure how to apply this information and if there is any other information I should know before attempting to answer the question?