How do I access the -1 above some things?

Press "2nd", then press the button. The inverses will pop up.

What button, kitty<3?

For example, DragonSlayer, suppose you want to use the inverse sine. The button that shows up on the calculator's home screen would be "sin".

To get the inverse sine (also caled arcsine) you would first press the "2nd" button in the top left corner. (See it?) Then you would press the button where "sin" had been. It now shows up as "asin", the inverse sine.

Ah, I now get it. Thanks, kitty<3