Solution
= Solution
Here $u=-2\sinh(\lambda x)$ and $D=\cosh(\lambda x)$. Zero stationary flux gives $(DP)'=uP$, so $P\propto D^{-1}\exp\int u/D,dx\propto\cosh(\lambda x)^{-(1+2/\lambda)}$, a symmetric unimodal distribution.
= Solution
Here $u=-2\sinh(\lambda x)$ and $D=\cosh(\lambda x)$. Zero stationary flux gives $(DP)'=uP$, so $P\propto D^{-1}\exp\int u/D,dx\propto\cosh(\lambda x)^{-(1+2/\lambda)}$, a symmetric unimodal distribution.