ASIN function
Returns the arcsine of a number, for example, the angle whose sine is number.
Syntax
ASIN(number)
Remarks
The input value must be in the range -1 <= number <= 1, or a #NUM! error is returned. The resulting angle is in the range -PI/2 <= angle <= PI/2 radians (-90 <= angle <= 90 degrees).
Example
ASIN(1)
Equals 90 deg.