Specifically, they are the inverses of the sine, cosine, tangent, cotangent, secant, and cosecant functions, and are used to obtain an angle from any of the angle's trigonometric ratios. Inverse trigonometric functions are widely used in engineering, navigation, physics, and geometry. I'm not sure what your entering the expression into, but if it's a graphing calculator, the arcsine function is listed as sin⁻¹ and should be the same button as sin. Press 2nd, then sin.
