Is It Possible to Have Bounded Partial Derivatives Without Differentiability?

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The discussion centers on the relationship between bounded partial derivatives and differentiability in calculus. A key example provided is the function f(x) = |x|, which has bounded derivatives (|f'(x)| ≤ 1) but is not differentiable at x = 0. In contrast, the function f(x) = x² is differentiable everywhere, yet its derivative is unbounded. This illustrates that boundedness of partial derivatives does not imply differentiability.

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Diffy
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Is it possible to have a function that has bounded paritial derivatives, but is not differential? Can you give me an example? And if possible explain how this is possible?

I am having trouble understanding this calculus concept. Thanks.
 
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I assume that you meant "differentiable" instead of "differential"?

How about f(x) = |x|.
For all x, [tex]|f'(x)| \le 1[/tex]
however, f(x) is not differentiable.

The boundedness of partial derivatives and differentiability don't have much to do with each other. On the other hand, for example, the derivative of f(x) = x2 is unbounded although f(x) is perfectly well differentiable (infinitely often, even).
 

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