DOUBLE asin(DOUBLE x) Returns the arc sine of x, or nan if x is not in the range -1 to 1.
mysql> select asin(0.5); +---------------------+ | asin(0.5) | +---------------------+ | 0.52359877559829893 | +---------------------+ mysql> select asin(2); +-----------+ | asin(2.0) | +-----------+ | nan | +-----------+
ASIN