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.