/ ________\ | / 2 | atan\\/ x - 1 /
atan(sqrt(x^2 - 1))
/1 1 \ -|-- + -------| | 2 2| \x -1 + x / ---------------- _________ / 2 \/ -1 + x
2 1 3*x -- + ----------- + ---------- 3 / 2\ 2 x x*\-1 + x / / 2\ \-1 + x / ----------------------------- _________ / 2 \/ -1 + x