int(x^(4)-1)/(x^(2)sqrt(x^(4)+x^(2)+1))dx=

int((x^(4)-1)dx)/(x^(2)sqrt(x^(4)+x^(2)+1))

int(x^(2)-1)/(x^(3)sqrt(2x^(4)-2x^(2)+1))dx is equal to

int ((x^(4)-1)dx)/(x^(2)sqrt(x^(4)+x^(2)+1))

int (x^(2)-1)/(x^(3)sqrt(2x^(4)-2x^(2)+1))dx=

int(x)/(x^(2)sqrt(x^(4)-1))dx

int(x^(2)-1)/(x sqrt(1+x^(4)))dx

int((x^4-1)dx)/(x^2sqrt(x^4+x^2+1))

int(x)/(sqrt(x^(4)+x^(2)+1))dx=

int(x^4-1)/(x^2sqrt(x^4+x^2+1))dx= sqrt(x^2+1/(x^2)+1)+C (sqrt(x^4+x^2+1))/(x^2)+C (sqrt(x^4+x^2+1))/x+C (d) none of these