Most Difficult Math Class?

I'm a freshman in college right now, and I'm getting ready to take my Calculus II final here later this week.  I've always been very good at math, but this last semester was by far the most difficult math I've ever taken.  For the first time in my life, I'm actually having to study outside of class, and I'm not certain of at least a high B on this test.

From talking to some of my sophomore buddies and a few of the teachers I'm on good terms with I've heard that Calc II is about the hardest math I will ever take.  Would you guys agree? If not, what was the most difficult math for you?

>>38
I mean that it's closure doesn't intersect with any nowhere dense sets. Why? Because the closure of the nowhere dense set is a closed set containing no open set, so within any open set, there is at least one point not within its closure. This means that there is an open sphere centered upon that point not intersecting that nowhere dense set. Choose one such open sphere, take the open sphere with half its radius, and then take the closure of that sphere.