" (ii) "int_(1)^(2)(x^(2)+1)/(x^(4)+1)dx

int_(-1)^(1)(x^(2)-1)/(x^(2)+1)dx=

int_(-1)^(1)(x^(2)+x)/(x^(2)+1)dx=

int_(0)^(2)((x^(4)+1))/((x^(2)+1))dx

int_(1)^(4)(x^(2)-x)dx

int_(-1)^(1)(1-x^(2))/(1+x^(2))dx is

int_(1)^(4)(x^(2) - x)dx .

int_(1)^(2) (1)/(2(1+x^(4)))dx

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

(i) int((x^(2) - 1)/(x^(2) + 1))dx , (ii) int ((x^(6)- 1)/(x^(2) + 1))dx (iii) int ((x^(4))/(1+x^(2)))dx , (iv) int((x^(2))/(1+x^(2)))dx