Synopsis
double asin(double x);
Description

asin returns the principal value, in radians, of the inverse circular sine of x. The principal value lies in the interval [??, +?] radians.

If |x| > 1, errno is set to EDOM and asin returns HUGE_VAL.

If x is NaN, asin returns x. If |x| > 1, asin returns NaN.