It still means rotation in "a + bi". If you take "a + b" you get another real number, but if you take "a + bi", the b component has been rotated by 90 degrees (i), and now it's orthogonal to a. Even if we drop complex numbers, it's not like we write out points in polar coordinates as "5 + 30 degrees" - how are you adding a length and an angle together?
Yeah, I see now. “times i” is discrete 90 degree rotation itself, not just ‘i’, nor ‘b’. Thanks everyone for making that clear.
This though shows that explanations via analogies or non-strict wording may confuse one rather than enlighten. I’m not good at math, but once understood to not search analogies or geometry in things. Instead it is better to “shut up and calculate”. Not sure if imagining something is required to manage it. It’s only our brain’s faulty quirk.
