x*atan(x) 2 --------- + x 1
(x*atan(x))/1 + x^2
x 2*x + ------ + atan(x) 2 1 + x
/ 2 \ | 1 x | 2*|1 + ------ - ---------| | 2 2| | 1 + x / 2\ | \ \1 + x / /
/ 2 \ | x | 8*x*|-1 + ------| | 2| \ 1 + x / ----------------- 2 / 2\ \1 + x /