The *inverse sine* of , denoted by
,
is defined as the unique value
satisfying
.
The inverse sine function ``
'' is also known as
the *arcsine* function ``.''

**Domain and range of .**
and
.

**Trigonometric equation.**
Consider the solutions
in the cycle to the equation
.
By observing
,
we obtain the two solutions and as

When or , we find ; thus, there is only one solution in the interval .

Department of Mathematics