The C library function double asin(double x) returns the arc sine of x in radians.
double asin(double x)
#include #include #define PI 3.14159265 int main () { double x, ret, val; x = 0.9; val = 180.0 / PI; ret = asin(x) * val; printf("The arc sine of %lf is %lf degrees", x, ret); return(0); }
The arc sine of 0.900000 is 64.158067 degrees