(i) `int_(1)^(oo)(dx)/(x^(2)(x+1))`

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

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

int_(1)^( oo)(1)/(x)dx=

Evaluate : (i) int_(-oo)^(oo) (dx)/(x^(2)+2x+2) , (ii) int_(sqrt(2))^(oo)(dx)/(xsqrt(x^(2)-1)) , (iii) int_(0)^(4)(x^(2))/(1+x)dx (iv) int_(0)^(pi//2) sqrt(costheta)sin^(3)theta

36.Find the following integrals iii) int_(1)^(oo)(dx)/(x^(1.4)) v) int_(-5)^(-2)(1)/(1-x)dx vil int_(0)^(1)(a+bx)^(2)dx

int_(0)^(oo)(1)/(3+x^(2))dx

int_(3)^(oo)(3)/(x^(2)-1)dx

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