Does the Order of Differentiation Matter?

  • Context: Undergrad 
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    Differential Matter
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Discussion Overview

The discussion revolves around the order of differentiation in the context of mixed partial derivatives and whether the order affects the outcome. Participants explore the conditions under which mixed derivatives are equal and the concepts of total differentials versus normal differentials.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the order of differentiation matters in the context of mixed derivatives.
  • Another participant states that if a function and its first and second derivatives are continuous in a neighborhood of a point, the mixed derivatives are equal at that point.
  • A participant expresses confusion about the terms "total differential function" and "normal differential property," indicating a lack of clarity on these concepts.
  • Another participant clarifies that the discussion does not involve a "total differential" but is focused on the properties of partial derivatives.

Areas of Agreement / Disagreement

There appears to be some agreement on the conditions under which mixed derivatives are equal, but confusion remains regarding the terminology used and the distinction between total and normal differentials. The discussion does not reach a consensus on these terms.

Contextual Notes

Participants express uncertainty about the definitions of total differentials and normal differentials, which may affect their understanding of the topic.

quietrain
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is this the same? why are they the same? do the order of differential not matter?

d/dxi (dyj / dxj) = d/dxj (dyj / dxi)

where LHS : differentiate yj w.r.t xj first, then xi

while RHS: differentiate yj w.r.t xi first, then xj

thanks!
 
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As long as f and its first and second derivatives are continuous, in some neighborhood of a point, the "mixed" derivatives
[tex]\frac{\partial f}{\partial x\partial y}[/tex]
and
[tex]\frac{\partial f}{\partial y\partial x}[/tex]
are equal at that point.
 
is this a total differential function? or is it just a normal differential property?

i seem to be mixing everything up :(
 
I have no idea what you are asking. I don't know what you mean by "total differential function" (I do know what a total differential is) or 'normal differential property".

There is no "total differential" in this problem. It is entirely a property of partial derivatives.
 
ah i see than kyou
 

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