Oh man I hate them.
After playing with my calculator, I have found out that the limit as x->∞ of the arctan(x) is π/2, the arcsec(x) as x->1 = ∞, and little else.
Anything else I should be aware of before trying to do crazy-seeming Improper Integrals problems that look divergent but they actually converge because goshdarn it, wouldn't you just know the arctan(∞) happens to be π/2?