Sin Definition and 452 Threads

sin hx, cos hx, tan h x... What are they? What does the "h" mean here? Any explanations or websites would be appreciated. :smile:

I encountered this problem in a set of limit problems: Limit[ Sin[ Sin[x] ] / x , x-> 0 ] According to what my book says, if the interior function in the sine approaches zero and the denominator also approaches zero, then the limit is 1; which, as I verified, is the answer. But is there a...