English: The arctangent function can be used to find the angle of a point (x, y), using arctan(y/x). Unfortunately, because y/x is the same as (−y)/(−x), this conflates pairs of opposite points, and does not return the intended angle whenever x is negative. The 2-argument arctangent function does not have this problem.
When x < 0, the two-argument arctangent differs from arctan. If y > 0, by −π radians, or if y < 0, by π radians. When x > 0, the two functions have the same result.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.