`underset(0)overset(oo)int (x)/((1+x)(1+x^(2)))dx`

Evaluate the following integrals: underset(0)overset(1)int(2x)/(1+x^2)dx

Evaluate the following integrals : underset(0)overset(1)int(2x-1)/(1+x-x^2)dx

underset0overset1 int (1-x)/(1+x)dx

underset0 overset1 int (dx)/(1+x^2)

Evaluate the following integrals: underset(0)overset(1)int(x)/(x^2+1)dx

If I_(1)=int_(0)^(oo) (dx)/(1+x^(4))dx and I_(2)=underset(0)overset(oo)int x^(2)(dx)/(1+x^(4))"then"n (I_(1))/(I_(2))=

underset0overset1int(dx)/(2e^x-1)

Let I= underset(0)overset(1)int (x^(3)cos 3x)/(2+x^(2))dx . Then

underset0overset1int (2x)/((x^2+1)(x^2+2))dx

underset0 overset infty int x/((1+x)(1+x^2))dx =