What is the difference between curly and derivative (d) sign

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Discussion Overview

The discussion revolves around the difference between the curly derivative (partial derivative) and the regular derivative (d) in the context of energy as a function of multiple variables, specifically in relation to multivariable calculus. Participants seek to clarify the mathematical expressions involved and their physical interpretations.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant asks for clarification on the expression involving the derivative of energy (dE) and the difference between curly and derivative signs.
  • Another participant explains that the curly derivative refers to a partial derivative, applicable when dealing with functions of multiple variables.
  • A different participant notes that the last expression involves taking the partial derivative of energy with respect to each variable k and summing them, referencing the property that the derivative of a sum equals the sum of the derivatives.
  • One participant mentions that this topic is covered in multivariable calculus.
  • A further inquiry is made regarding the physical meaning of the quantity ∂E/∂k1 * dk1.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the mathematical concepts, and while some explanations are provided, there is no consensus on the physical interpretation of the quantities involved.

Contextual Notes

The discussion touches on concepts from multivariable calculus, but does not resolve the physical implications of the derivatives mentioned, nor does it clarify all assumptions related to the expressions.

masyousaf1
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Dear All,

Please see the image below in attachment where Energy is function of K. I want to understand how is it possible to understand the last expression ( dE = ? ). Additionally, what is the difference between curly and derivative (d) sign ?

Many thanks to the mentors on this forum
Best wishes
 

Attachments

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    11081629_621642291300641_53002714_n.jpg
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the "curly" derivative (d) sign is called a partial derivative, and is when you only take derivative of a function that has multiple variables. It works very similar to a regular derivative.
 
The last expression is just taking the partial derivative of E with respect to each k, and summing them up since the derivative of the sum is the sum of derivatives!
 
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Likes   Reactions: masyousaf1
This subject is covered in multivariable calculus
 
Thanks RaulTheSCSlug, kindly mention what is the physical meaning of the quantity ∂E/∂k1 * dk1 .

Best wishes
 

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