Can I perform inverse trig functions in Spotlight? Is there a way to make Spotlight return the sin-1, cos-1, or tan-1 of a given number without opening Calculator.app?
asin(x), acos(x), and atan(x) work for me. Spotlight gives the results in radians and will not show any calculator results if you go out of the domains for these functions.

Edit: If you want the results in degrees instead of radians, use asind(x), acosd(x), and atand(x).