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I just started Calculus 3 and I thought it would be useful to see images of functions to get used to the transition of visualizing in 3-dimensions. I was wondering how one would go about plotting a function like:
$$x^2 - y^2 + xy$$
And what would be the code to find its maxima and minima? I have never used Mathematica before so it would be of big help if you could show me the way to plot functions like this one. Thanks a lot.