∫x+1x2+1 dx =
12log|x2−1|+cos−1x+c
12log|x2−2|+tan−1x+c
12log|x2+1|+tan−1x+c
12log|x2−1|−tan−1x+c
∫xx2+1 dx + ∫1x2+1 dx
=12log|x2+1|+tan−1x+c