Given a scalar-valued function [tex]f=f(x,y)[/tex], if it's true that [tex]\frac{\partial^2 f}{\partial x \partial y}=\frac{\partial^2 f}{\partial y \partial x}[/tex], what does that tell about function [tex]f[/tex]? Does it mean that it's continuous, or does it need to be smooth, or...?(adsbygoogle = window.adsbygoogle || []).push({});

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# Order of partial derivatives

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