Let $p(x)$ be a continuous probablity density function on the interval $x\in[0,1]$, subject to the constraint $p(x)=0$ whenever $x\le0$ or $x\ge1$. Assume that the expected value of $p(x)$ is known and fixed:
$$\int_0^1 p(x)x\mathrm{d}x=\mu$$
What's the continuous probability density function $p(x)$ of maximum entropy satisfying these constrainsts? Note that I require that $p(x)$ is continuous on the interval $[0,1]$, so the answer cannot be a truncated exponential distribution, as Boltzmann's theorem would seem to suggest, because a truncated exponential distribution is discontinuous at the endpoints $x=0$ and $x=1$.