What Are Infinitesimals of Order Higher Than Δx, Δy, and Δz?

  • Context: Graduate 
  • Thread starter Thread starter koustav
  • Start date Start date
  • Tags Tags
    infinitesimals
Click For Summary

Discussion Overview

The discussion revolves around the concept of "infinitesimals of order higher than Δx, Δy, and Δz" as mentioned in a mathematical expression related to changes in a variable θ. Participants explore the implications of these higher-order infinitesimals in the context of calculus and differential expressions.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant seeks clarification on what is meant by "infinitesimals of order higher than Δx, Δy, and Δz."
  • Another participant suggests that higher-order infinitesimals can be understood in terms of powers, noting that squares and cubes of small quantities are even smaller.
  • A different participant counters that the original expression does not explicitly include square or cube terms, prompting further clarification.
  • One participant elaborates on the concept by expanding the expression for Δθ to include second-order terms, indicating that these terms represent the infinitesimals of higher order.

Areas of Agreement / Disagreement

Participants express differing views on the presence and significance of higher-order terms in the expression, indicating that the discussion remains unresolved regarding the interpretation of these infinitesimals.

Contextual Notes

The discussion highlights the potential ambiguity in the definitions and applications of higher-order infinitesimals, as well as the dependence on the context of the mathematical expression being analyzed.

koustav
Messages
29
Reaction score
4
in a certain problem it was written Δθ=∂θ/∂x*Δx + ∂θ/∂y*Δy + ∂θ/∂z*Δz + infinitesimals of order higher than Δx,Δy and Δz.can anyone tell me what is "infinitesimals of order higher than Δx,Δy and Δz?"
 
Physics news on Phys.org
Squares, cubes and so on.

For "a" tiny, a^2 is even tinier.
 
yes but there are no square or cube terms inthe expression
 
Sure there are. It's the "infinitesimals of order higher than Δx,Δy and Δz". Expanding that Δθ to incorporate some of the second order terms yields

Δθ = (∂θ/∂x)Δx + (∂θ/∂y)Δy + (∂θ/∂z)Δz
+ (1/2)((∂2θ/∂x2)Δx2 + (∂2θ/∂x∂y2)ΔxΔy + (∂2θ/∂x∂z2)ΔxΔz + (∂2θ/∂y∂x2)ΔyΔx + ∂2θ/∂y2)Δy2 + ···)
+ terms of order three and higher.
 
  • Like
Likes   Reactions: koustav

Similar threads

  • · Replies 22 ·
Replies
22
Views
3K
  • · Replies 40 ·
2
Replies
40
Views
7K
  • · Replies 6 ·
Replies
6
Views
12K
  • · Replies 38 ·
2
Replies
38
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
4K
Replies
9
Views
7K
  • · Replies 3 ·
Replies
3
Views
6K
Replies
3
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K