[phaer]

I don't think its that easy, it depends more on the specific school and most of all on the teacher. For the record: I also had to memorize it and i went to an "european" school, or rather to an austrian one. Europe still has a wide variety of education systems.

[Locke1689]

Same with the US. Very variable.

We went through the unit circle derivation in the 8th grade and were thus showed why cos is conventionally x and sin conventionally y.

[riffraff]

and not all systems are uniform. I went to high school in Italy and changed something like 4math teachers.

One of them explained the x/y thing, another didn't.