The domain of the mathematical function arcsin is -1 to 1. The domain defines the possible input value for a particular function. This means the input value for arcsin, the inverse trigonometric function of sine, is never greater than 1 and never less than -1.
Bloodstain analysts use the arcsin in the analysis of blood splatter patterns at crime scenes. After they measure the length of the blood splatter, they can use the arcsin function to help determine the location of the victim in the room and the type of weapon used. Like the sine function, arcsin does not provide distinct numbers, meaning it is inexact and provides multiple values. Trigonometry calculators typically have an arcsin button, allowing for easy calculation.