The function $$f(x) = {{{x^2}} \over {{e^x}}}$$ is monotonically increasing, if

If $${x^a}{y^b} = {(x - y)^{a + b}}$$, then the value of $${{dy} \over {dx}} - {y \over x}$$ is equal to

If $$s = \sqrt {{t^2} + 1} $$, then $${{{d^2}s} \over {d{t^2}}}$$ is equal to

Let $$f(x) = {(\left| x \right| - \left| {x - 1} \right|)^2}$$

What is f'(x) equal to when x > 1 ?