I stopped at Trig...I looked at the pre-Calc textbook in high school and had no idea what I was looking at beyond the fact that it was math or math-based. Hey, I was selecting courses for my junior year and was not really trying to get into anything too tough. I opted for advanced algebra and geometry (single semester courses) and sailed (comparatively speaking, I would've flunked out of pre-Calc I'm reasonably sure).
Ivan, thanks for sharing, I'm going to check into that book.