.. efun:: float atan2(int|float y, int|float x)

  Returns the angle part of the polar coordinates of the point (x, y) in the range (-pi, pi).

  Note the exchange of the coordinates x and y in the parameter list reflecting the sequence in the gradient to angle transformation ``atan(y / x)``.

  :history 3.2.9 changed: added integers as arguments

  .. seealso:: :efun:`sin`, :efun:`cos`, :efun:`tan`, :efun:`asin`, :efun:`acos`, :efun:`atan`