asin
(PHP 3, PHP 4 , PHP 5)
asin -- Arc sine
Description
float
asin ( float arg)
Returns the arc sine of arg in radians. asin() is the complementary function of sin(), which means that a==sin(asin(a)) for every value of a that is within asin()'s range.
Смотрите также: asinh(), acos(), and atan().