Pro tip: a problem might look on first sight just like one you've seen, but you still have to read it all the way through to make sure.
I say that since I'm seeing that same mistake again & again on HW9 ... the second problem was nearly like one from last year, but the second part was different in a crucial way. By "different" I mean "not even remotely close."
Let's recap: when you see a familiar-looking problem tomorrow, it might be a trap. Make sure I haven't changed anything key before you just go solving stuff all willy-nilly.
And, a bonus pro-tip: don't forget your calculator. There may actually be numbers other than pi and 2 on the exam. I think a 7 got in there while I wasn't looking.