∫ x^(4) / x^(2) - 1 dx
∫ x^4dx /( x^2 – 1)=∫ (x^4-1+1)dx /( x^2 – 1)= =∫ (x^4-1)dx /( x^2 – 1)+ ∫ (1dx /( x^2 – 1))= = ∫ (x^2+1)dx)+ ∫ (1dx /( x^2 – 1))= =(x^3/3)+x + (1/2) ln |(x-1)/(x+1)| + C