/ _________\ atan\\/ 4*x - 1 /
atan(sqrt(4*x - 1))
1 --------------- _________ 2*x*\/ 4*x - 1
/ 1 1 \ -|-------- + ---| \-1 + 4*x 2*x/ ------------------ __________ x*\/ -1 + 4*x
1 6 2 -- + ----------- + ------------ 2 2 x*(-1 + 4*x) x (-1 + 4*x) ------------------------------- __________ x*\/ -1 + 4*x