ASIN
Returns the arcsine of a number, the angle whose sine is this number. The angle is in radians, in the range -pi/2 to pi/2.
Syntax
ASIN(number)
Number is the sine of the desired angle, and must be a number between -1 and 1.
Comments
In order to express the arcsine in degrees, you have to multiply the result by 180/pi(), or use the DEGREES function.