-1 ----------------- / 2\ 2 \1 + x /*atan (x)
/ 1 \ 2*|x + -------| \ atan(x)/ ------------------ 2 / 2\ 2 \1 + x / *atan (x)
/ 2 \ | 4*x 3 6*x | 2*|1 - ------ - ----------------- - ----------------| | 2 / 2\ 2 / 2\ | \ 1 + x \1 + x /*atan (x) \1 + x /*atan(x)/ ----------------------------------------------------- 2 / 2\ 2 \1 + x / *atan (x)