log(|x|)
sign(x) ------- |x|
2 sign (x) 2*DiracDelta(x) - -------- + --------------- 2 |x| x
/ 2 \ |sign (x) DiracDelta(x, 1) 3*DiracDelta(x)*sign(x)| 2*|-------- + ---------------- - -----------------------| | 3 |x| 2 | \ x x /