atan(2*x - 3)
d --(atan(2*x - 3)) dx
      2       
--------------
             2
1 + (2*x - 3) 
              -8*(-3 + 2*x)   
------------------
                 2
/              2\ 
\1 + (-3 + 2*x) / 
               /                  2 \
   |      4*(-3 + 2*x)  |
16*|-1 + ---------------|
   |                   2|
   \     1 + (-3 + 2*x) /
-------------------------
                     2   
    /              2\    
    \1 + (-3 + 2*x) /