negative sine

What do you mean?

- Negative sine?

$-\sin \theta$?

- Arcsine?

$\sin^{-1}\theta$?

For negative sine just type "-sin()"

Arcsine just type "asin()"

To make your question right its "How do I put the negative sign on this site (calculator).

All you have to do is press the key on keyboard right of "0".

or 

Ask Press the help button to help you you need to be more clear for question