The asin functions compute the principal value of the arc sine of x in the range [-pi/2,pi/2] radians for x in the domain [-1,1]. The asind functions compute the principal value of the arc sine of x in the range [-90,90] degrees for x in the domain [-1,1]. When abs(x) is greater than 1.0, the value of asin(x) is 0, and errno is set to EDOM.