The atan function simply computes the inverse tangens of a value. The atan2 function takes two values (y and x). This function is used to convert from cartesian coordinates (x,y) to polar coordinates (r,phi), where phi=atan(y,x).

http://stackoverflow.com/questions/283406/what-is-the-difference-between-atan-and-atan2-in-c

If you type the commands 'help atan' & 'help atan2', you get quick replies!

>> help atan

ATAN Inverse tangent.

ATAN(X) is the arctangent of the elements of X.

See also ATAN2.

Overloaded methods

help sym/atan.m

>> help atan2

ATAN2 Four quadrant inverse tangent.

ATAN2(Y,X) is the four quadrant arctangent of the real parts of the

elements of X and Y. -pi

some information about atan2:

https://en.wikipedia.org/wiki/Atan2

atan is the general form of inverse tangent that gets a value and returns the associated angle in radian. But atan2 gets two values of y and x and assumes a complex number as x + iy and returns its phase.

furthermore, atan2(y,x) = atan(y/x).

hope this helps...