Suppose we have this random variable $X$, what can we say about $E(\frac{1}{X})?$
I alrealy proved to myself that it's not always implies that $E(\frac{1}{X})=\frac{1}{E(X)}$, but i know sometimes it does.
So, what can we say in general about $E(\frac{1}{X})?$ And when exactly does this equation $E(\frac{1}{X})=\frac{1}{E(X)}$ holds?