what is the difference between sin,sin^-1 and sinh^-1

You use sin when you have the angle and you are looking for a side (or a ratio)

You use inverse sin (sometimes called arc sin) when you have the sides or the ratio and you are finding the angle!

So sine to find a side and inverse sin to find the angle.

$$sin(angle)=\frac{opp}{hyp}\\ sin^{-1}\left(\frac{opp}{hyp}\right)=angle$$

sinh is a compicated thing that you probably wont use unless you study maths at a high level.

but if you are interested you can look here     http://en.wikipedia.org/wiki/Hyperbolic_function