If $$z=xy$$ $$ln(xy),$$ then

The maximum value of the function $$\,f\left( x \right) = \ln \left( {1 + x} \right) - x$$ (where $$x > - 1$$ ) occurs at $$x=$$________.

If $$\,{e^y} = {x^{1/x}}\,\,$$ then $$y$$ has a

For real values of $$x,$$ the minimum value of function $$f\left( x \right) = {e^x} + {e^{ - x}}\,\,$$ is