I have a general question: What do you need to prove that tangent plane of a function of multiple variables exists? Continuity is not enough: See Absolute value function. What are the components needed to prove this?

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anonymous · Answer

Whoops, by multiple variables, I meant TWO lol, since it is a tangent plane :P

anonymous · Answer

? Any answers here? I know how to find the tangent plane, that isn't the problem, I want to prove that this plane exists.

ikram002p · Answer

it needed to be smoth  no edges and contiues , for example
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