How do you find out what sin^-1(0,37) is?

hi aerdna, 

I expect you are using a comma instead of a decimal point.  I know some countries use a comma but I thinks most use a point :)

Anyway, enter is as

asin(0.37)

that should work just fine  :)

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}^{\!\!\mathtt{-1}}{\left({\mathtt{0.37}}\right)} = {\mathtt{21.715\: \!617\: \!283\: \!264^{\circ}}}$$

Yep, it did for me  :)