For the probability distribution given by following

Var(X) =

$$\int_\limits0^1|5 x-3| d x=$$

Function $$f(x)=e^{-1 / x}$$ is strictly increasing for all $$x$$ where

The distance between the parallel lines $$\frac{x-2}{3}=\frac{y-4}{5}=\frac{z-1}{2}$$ and $$\frac{x-1}{3}=\frac{y+2}{5}=\frac{z+3}{2}$$ is