I have many functions with two variables $x$ and $y$, for which I need to compute min and max to see if they are in the range I want them to be. For example:
$z = 0.5 - 0.25 \cos(\pi x) - 0.25 \cos(\pi y),$ where $x\in[0,1]$ and $y\in[0,1]$.
I tried Wolfram Alpha but for some reason it does not compute the min and max.
Thanks