Greetings. I could really use some assistance on some homework questions. I've been working on them, but can't seem to make it far on them. Any help is appreciated. Thanks!

The first and second are improper integrals.

The first is:

∫(lower limit 3, upper limit ∞) dx/√(x + 1)

The second is:

∫(lower limit 0, upper limit 4) dx/√(4 - x)

The third is:

∫ 1/√(9 + x squared)dx