I'm having some trouble with a few problems, any hints or help would be great!

1) antiderivative of 1/(81-x^2)

i ended up getting this down to (1/9)integral of (1/cos(theta)), and i think the integral of that is (1/9)(ln(sec(theta)+tan(theta))), but it was wrong. any ideas? i may have just integrated the wrong thing, im not sure

2) antiderivative of 1/((16x^2+1)^2)

i have no idea where to begin with this one, haven't seen something of this type before

3)antiderivative of 1/((2x^2+2x+7)^2)

again, unsure of where to begin. should i multiply that all out, or what?