Hello, tester85!

I'll explain the first one for you.

It's quite challenging and uses a technique you may not have seen.

Integrate by parts . . .

. .

We have: .

Integrate by parts (again):

. .

We have: .

. .

. .

Multiply by

. . . . . . . .

Factor: .

. . . . . . . . . . .

Therefore: .