We are doing complex numbers, polar coordinates, Euler's formula etc in class and there is this thing called the Argument (Arg) function. I am having trouble understanding what this is. This is a new concept and sadly my notes aren't much help. So could someone kindly answer the following questions. what is this function? How do I evaluate it? Where is it used? Are there any properties of this function I should know about? Anything for further reading is also appreciated but keep in mind that this is the first I am seeing all this stuff. No wikipedia please because math on wikipedia doesn't make sense to me with all those complicated equations and symbols that I have never seen before. Here is a sample question from my assignment just to make sure I am getting my message across properly. Feel free to use it as an example if you want. z1 = [itex]\pi[/itex]/8 z2 = 3[itex]\pi[/itex]/4 find Arg (z1z2) Answer is 7[itex]\pi[/itex]/8 which just seems like simple addition so why go through all this trouble with Arg?