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