I'd like to go back to grad school, get my PhD, but it's been so long that I've forgotten all my math. I'm planning to start with high school geometry. If I c

I'd like to go back to grad school, get my PhD, but it's been so long that I've forgotten all my math. I'm planning to start with high school geometry. If I can find a copy, I'm going to use the same textbook as I used in high school. It was really good. Not sure about what I'll use for a trig textbook. For calculus I'll use Tom Apostol's Calculus vols I and II - that's what we used at Caltech.