asin

asin - Arc sine

float asin ( float $x )

Returns the arc sine of x 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.

Parameters:

x - The argument to process. It can be a scalar or an array.

Return Value:

The arc sine of x in radians. If x is an array, the return value will also be an array.

Version

1.0 and above.