(3*x + 1)*atan(2*x)
2*(3*x + 1) 3*atan(2*x) + ----------- 2 1 + 4*x
/ 4*x*(1 + 3*x)\ 4*|3 - -------------| | 2 | \ 1 + 4*x / --------------------- 2 1 + 4*x
/ / 2 \\ | | 16*x || 16*|-9*x + (1 + 3*x)*|-1 + --------|| | | 2|| \ \ 1 + 4*x // ------------------------------------- 2 / 2\ \1 + 4*x /