sin -1 how to do it

To do sin-1 on web2.0calc, it is not sin-1: It is asin()

So do asin(value) to get what you want :)

sin-1 is the inverse of sin. When you have sin(x) and you want to get x on its own on one side, you bracket the other side with sin-1.

Example:

sin(x)=3/5

x=sin-1(3/5)