I really need help with these numbers,I have forgotten all my Integration.HEEEEEELPP!!!!!!!?

Question

its been 5Yrs since I last did Integration so am kinda rusted.Please help me out here.Thanks in advance.
I actually got lots of amazing qns,I just dont want to keep losing points wen i ask qns,but here I go;

Integrate
∫1/(x^2 + a^2) dX

∫X^4/(1-X^2) dX

∫dY/(sqrt(Y^2+1)

Could you please remind me what this amounts to;
∫logX dX Thanx a bunch,You guys are the best

Answer 1

1)= 1/a*Arctan (x/a)+c
divide x^4 by(1-x^2) =
x^4= (-x^2-1)+1/(1-x^2) = (-1-x^2)+1/2(1/(1+x)+1/(1-x))
Int = -x-x^3/3+1/2 lnI1-x^2I +c

3)Int=ln(x+sqrt(1+x^2)) +c
Int lnx dx = xln x-x +c (Integration by parts)