Read the following information and answer the two items that follow :

Consider the equation x^y = e^{x $$-$$ y}

What is $${{dy} \over {dx}}$$ at x = 1 equal to ?

Read the following information and answer the two items that follow :

Consider the equation x^y = e^{x $$-$$ y}

What is $${{{d^2}y} \over {d{x^2}}}$$ at x = 1 equal to ?

What is the derivative of $${\sec ^2}({\tan ^{ - 1}}x)$$ with respect to x ?

If f(x) = sin (cos x), then f'(x) is equal to