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

Let  $x = \sec \theta - \cos \theta \text{ and } y = \sec^4 \theta - \cos^4 \theta \\ $ 

What is $(\frac{dy}{dx})^2$ equal to?