I've been doing some work on Complex Numbers. In the description of the picture I attached above, it states "|z_2 - z_1 | = AB, and arg(z_2-z_1) is the angle between the vector AB and the positive direction of the x-axis"
I don't seem to understand where the angle between vector AB and the positive direction of the x-axis would be. For example, for a vector OP, where O is the origin, I know that the argument would be between OP and the positive x-axis. But I cannot seem to visualise where the argument for AB would be.
I hope someone can make sense of what I'm asking, thanks in advance.