/ _____\ atan\\/ 2*x /*4
atan(sqrt(2*x))*4
___ 2*\/ 2 --------------- ___ \/ x *(1 + 2*x)
___ / 1 1 \ -4*\/ 2 *|------- + ---| \1 + 2*x 4*x/ ------------------------ ___ \/ x *(1 + 2*x)
___ / 4 3 1 \ 4*\/ 2 *|---------- + ---- + -----------| | 2 2 x*(1 + 2*x)| \(1 + 2*x) 8*x / ----------------------------------------- ___ \/ x *(1 + 2*x)