Library: Trigonometry (OMTRIG legacy)
Returns: The arc sine of the floating point value.
define external float function asin value float x
Use asin to calculate, in radians, the arc sine (inverse sine) of a floating point number. This trigonometric function works the same way as its equivalent in the C math library.
Out-of-range values, (|x| > 1), return "not a number" (NaN).
The following sample shows how to use
asin to calculate the value of the arc sine of 0.999. The result is 1.526071239626164.