S1 : If $$-$$7 is an integer, then $$\sqrt{-7}$$ is a complex number

$$\mathrm{S} 2$$ : $$-$$7 is not an integer or $$\sqrt{-7}$$ is a complex number

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