Page "Inverse function" Paragraph 33

However, the expression sin < sup >− 1 </ sup > x usually does not represent the multiplicative inverse to sin x, but the inverse of the sine function applied to x ( actually a partial inverse ; see below ).

To avoid confusion, an inverse trigonometric function is often indicated by the prefix " arc ".

For instance, the inverse of the sine function is typically called the arcsine function, written as arcsin, which is, like sin, conventionally denoted in roman type and not in italics ( note that software libraries of mathematical functions often use the name < tt > asin </ tt >):