integral 4t/(t^2-1)^2 dt

Int 4t/(t^2 - 1)^2 dt
= Int 4t (t^2 - 1)^-2 dt

Misal
u = t^2 - 1
du = 2t dt => dt = du/2t

= Int 4t . u^-2 . du/2t
= Int 2 u^-2 du
= 2/-1 u^-1 + C
= -2/u + C
= -2/(t^2 - 1) + C