Two Problem: find $\max, \min$; number theory: find $x, y$ 
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*Find $x, y \in \mathbb{N}$ such that $$\left.\frac{x^2+y^2}{x-y}~\right|~ 2010$$

*Find max and min of $\sqrt{x+1}+\sqrt{5-4x}$ (I know $\max = \frac{3\sqrt{5}}2,\, \min = \frac 3 2$)


Problem 1: I have read a similar problem with a good solution in this forum
