Show that for all $f \in \mathscr { C } _ { b } ^ { 2 }$, $f$ admits an entropy relative to $\mu$ and that $$\operatorname { Ent } _ { \mu } ( f ) \leqslant \int \left| f ^ { \prime } ( x ) \right| ^ { 2 } \mu ( x ) d x$$ You may consider the family of functions defined by $f _ { \delta } = \delta + f ^ { 2 }$ for $\delta > 0$.
Show that for all $f \in \mathscr { C } _ { b } ^ { 2 }$, $f$ admits an entropy relative to $\mu$ and that
$$\operatorname { Ent } _ { \mu } ( f ) \leqslant \int \left| f ^ { \prime } ( x ) \right| ^ { 2 } \mu ( x ) d x$$
You may consider the family of functions defined by $f _ { \delta } = \delta + f ^ { 2 }$ for $\delta > 0$.