f(x) is a continous function in R. i need to prove that if f(x)>=x^{2} for every x at R, so f(X) gets a minimum at [0,infinty). thanks!

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Originally Posted by orir f(x) is a continous function in R. i need to prove that if f(x)>=x^{2} for every x at R, so f(X) gets a minimum at [0,infinty). It is not true:

Last edited by Plato; April 9th 2013 at 04:17 PM.

but isn't it still a minimum? after all, still f(x0)<=f(x) [for every x at [0,infinity)] or not?

Originally Posted by orir but isn't it still a minimum? after all, still f(x0)<=f(x) [for every x at [0,infinity)] Again, this may be a translation difficulty. What does "f(X) gets a minimum at [0,infinty)" mean? The function I gave you does have a minimum at every point in , but on others.

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