-1 ----------- 4*(1/2 + x)
-1/(4*(1/2 + x))
-1 ------- 2 + 4*x
-1/(2 + 4*x)
-1/(2*(1 + 2*x))
-1 ----------- 2*(1 + 2*x)
-1/(2.0 + 4.0*x)
-2 ------- 4 + 8*x
-2/(4 + 8*x)