Question 1025361
The last two can be evaluated using simple substitution.  (Let the denominator be equal to w, or z, say.)

The first (two??) doesn't require substitution, however.

(Note:  {{{int(dx/(x^2+1)) }}}= {{{tan^-1(x)}}}, and doesn't require SIMPLE substitution although some people who like to split hairs may say let w = {{{tan^(-1)(x)}}}, for example.)