(PHP 4, PHP 5, PHP 7)
Arc tangent
float atan ( float $arg )
Returns the arc tangent of arg in radians. atan() is the complementary function of tan(), which means that a==tan(atan(a)) for every value of a that is within atan()'s range.
Parameters:
arg
The argument to process
Returns:
The arc tangent of arg in radians.
See also:
tan() -
atanh() -
asin() -
acos() -
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