Using Chain Rule to Find du/dT & du/dv: Step-by-Step Guide

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Discussion Overview

The discussion focuses on applying the chain rule to determine how a function u, defined as u = u(T,v), changes with respect to the variables T and v. Participants explore the mathematical steps involved in this process, particularly in the context of multivariable calculus.

Discussion Character

  • Technical explanation

Main Points Raised

  • One participant asks how to use the chain rule to express the change of u with respect to T and v, indicating an understanding of the chain rule as a derivative relationship.
  • Another participant provides a formulation of the chain rule under the assumption that T and v are functions of x, presenting the equation du/dx = (∂u/∂T)(dT/dx) + (∂u/∂v)(dv/dx).
  • A subsequent post reiterates the same chain rule formulation, expressing gratitude for the response.
  • One participant inquires about the difference between the symbols ∂ and d, seeking clarification on their meanings in the context of derivatives.
  • A participant explains that ∂ (partial derivative) is used in multivariable calculus to denote the derivative of a function with respect to one variable while treating others as constants, providing an example with a function F.
  • Another participant is prompted to find the partial derivative of F with respect to y, suggesting a collaborative exploration of the topic.
  • A participant responds with a proposed solution for the partial derivative of F with respect to y, expressing confidence in their answer.
  • Another participant agrees with the proposed solution, indicating a shared understanding.
  • One participant expresses appreciation for the assistance received in the discussion.

Areas of Agreement / Disagreement

Participants generally agree on the application of the chain rule and the meanings of the symbols involved, but there is no explicit consensus on the correctness of the proposed solutions or interpretations of the derivatives.

Contextual Notes

The discussion does not resolve the differences in understanding the application of the chain rule or the implications of using partial versus total derivatives. There may be assumptions about the relationships between variables that are not fully explored.

sphyics
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If a function is given by u = u(T,v) how to use the chain rule to write how u changes with respect to T & v.
Please specify the steps involved.
i understand chain rule as \frac{du}{dx} = \frac{du}{dy} \frac{dy}{dx}
 
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Assuming T and v are both functions of x, the chain rule gives:
du/dx = (∂u/∂T)(dT/dx) + (∂u/∂v)(dv/dx)
 
mathman said:
Assuming T and v are both functions of x, the chain rule gives:
du/dx = (∂u/∂T)(dT/dx) + (∂u/∂v)(dv/dx)
very much thanks for ur quick response :)

how does the symbol differs in meaning with d
 
\partial (read "partial") is basically the equivalent of d in multivariable calculus, it means you take the derivative of a function with respect to a variable while considering all other variables as constants during that operation.

For example if I have
F = x^2 + 2xy + \frac{x}{y}
Then
\frac{\partial F}{\partial x} = 2x + 2y + \frac{1}{y}
Can you find \frac{\partial F}{\partial y}? :)
 
JHamm said:
<br /> Can you find \frac{\partial F}{\partial y}? :)
<br /> <br /> = 2x - x/y<sup>2</sup><br /> <br /> i think that&#039;s the right answer :)
 
I think so too :)
 
Appreciate ur help :)
 

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