(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

f(x,y,z)=(xy+yz+xz)/(1+x^2+y^2+z^2)

Explain why f has no absolute maximum or minimum. How about critical points?

2. Relevant equations

Hint: it is simplest to make 3 cases: a) x+y+z does not =0 b) x+y+z=0 c) x=y=z=0

3. The attempt at a solution

I did cases b and c, but I'm not sure how to go about doing a. Also, I'm not sure how to explain why the function does not have an absolute max or min.

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# Homework Help: Finding critical points

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