I'm looking for someone validation. I am an engineering student doing calculations on power although I'm pretty sure its irrelevant.
Now from my mathematics high school days I always remember that when multiplying complex numbers you multiply the magnitude and add the angles and when doing division you divide the magnitudes and subtract the angles.
I am preparing for a national exam. We have been given previous past papers to help that come with the official answer sheets that were used in the previous national examinations and I'm staring at what seems impossible.
There are 3 sets of calculations. One for AB, BC and CA.
The first AB seems correct in that the angles have been added yet BC and CA the angles seem to have been subtracted. Am I missing something here? Is there something advanced about complex numbers and multiplication I don't know?