Talk:Differential equation

message: Old talk moved (along with page) to Talk:Ordinary differential equation. -- Walt Pohl 20:54, 23 Jan 2005 (UTC)

message: This article flows poorly. Obstructive clauses abound. There is also a decent amount of unnecessary language. I am going to attempt to fix it in a series of small edits so they can be reviewed. Would someone please double check what I do? I don't want to delete something important or add any mistakes of my own.   — Preceding unsigned comment added by 70.127.17.241 (talk) 13:48, 3 March 2020 (UTC)
thread_title:  Flow 

message: That table is quite useful to have, but its only on ODE's and should be moved to that article, also the nomenclature should be more standard (I'm in the process of rewriting that article).F = q(E+v×B) ⇄ ∑ici 10:02, 23 May 2012 (UTC)
thread_title:  remove ODE table 

message: The section Ordinary DE classification is already contained in Ordinary differential equation and places too much emphasis on ODEs for this article, which should balance PDEs and ODEs. I am going to remove most of that section (especially deleting the table) and modify the more general section Nomenclature to compensate. F = q(E+v×B) ⇄ ∑ici 07:08, 18 June 2012 (UTC)
thread_title:  Blend/remove classification summary and nomenclature sections 

message: this article is unclear, i made this edit -- http://en.wikipedia.org/w/index.php?title=Differential_equation&diff=516518566&oldid=516434444  — Preceding unsigned comment added by Coginsys (talk • contribs) 10:35, 8 October 2012 (UTC)
thread_title:  this article is unclear, i made this edit -- http://en.wikipedia.org/w/index.php?title=Differential_equation&diff=516518566&oldid=516434444 

message: look at the changes on http://en.wikipedia.org/w/index.php?title=Time_series&diff=518032407&oldid=516614772 
someone actually made it better
"In the context of...  the primary goal of time series analysis is forecasting"
...it is used for signal detection and estimation
can be used for clustering, classification, query by content, anomaly detection as well as forecasting
and they added important and significant sections
the article was just trash orginally and nobody was improving it
and then when you edit something, ppl dont improve it, all they do is change it back to the trash it was
Coginsys (talk)  —Preceding undated comment added 07:51, 16 October 2012 (UTC)
thread_title: very important example of what is good

message: The article says: "solutions —the set of functions that satisfy the equation" but is the class of solutions really always a set?  — Preceding unsigned comment added by 213.10.46.38 (talk) 15:30, 11 April 2013 (UTC)
replies: text: What is the problem? The class of all functions from a given set to a given set is a set; and every its subclass is. Boris Tsirelson (talk) 19:12, 11 April 2013 (UTC)
thread_title:  Is the class of solutions always a set? 

message: The Examples give formulas, but no indication of what real-world problems they relate to.  A non-expert might well be helped by knowing that a particular formula describes behaviors that they already know about in a non-mathematical context.  — Preceding unsigned comment added by RichMorin (talk • contribs) 05:41, 30 May 2013 (UTC)
replies: text: Seconded. As the it currently stands, the casual reader (such as myself) ends up with 42 browser tabs open with all the fancy math nerd terms used. Since those pages then reference other terms, the cycle is endless. An article this high on the list of frequently referenced math subjects should illustrate - with visuals and/or English - why exactly a differential equation is a differential equation, and show at least one example with a complete description of usage in a real-world scenario that can be followed with natural human intuition. Krushia (talk) 14:11, 12 December 2013 (UTC)
thread_title:  Add real-world grounding to the Examples 

message: As is too often the case, a perfectly sensible Wikipedia entry comes littered with colourful boxes sprinkled about by nit-wit editors.
 
The article has one of the funnier ones.  Before we get to the article at all we have a screenfull of edi-boxes, of which the first begins "This article or section lacks a single coherent topic."
 
One cannot help but be reminded of Will Rogers's "I am a member of no organized political party.  I am a Democrat."
 
Homeomorphically here, the article has no coherent topic.  It is about differential equations.
 
David Lloyd-Jones (talk) 05:13, 12 January 2014 (UTC)
replies: text: Two of them were added by a drive-by editor without any explanation. I removed them. -- Jitse Niesen (talk) 08:31, 14 January 2014 (UTC)
replies: text:  Actually, the editor did somewhat explain his reasoning when he added those tags (), but it is easy to miss. — Tobias Bergemann (talk) 11:16, 14 January 2014 (UTC)
replies: text: I stand corrected. No idea how I could have missed that. -- Jitse Niesen (talk) 13:57, 14 January 2014 (UTC)
thread_title:  'Nuther Inane Intrusion by a Wikipedia Editor 

message: More images helping to explain concepts or provide examples/representations would be nice. 
Differential Equations is an extremely rich field, but this wall of text does not do it justice. Even as a physicist, I am not engaged by this article... Now how interested do think an average teenager would be?
Here are some ideas: talk about analytically tractable vs. intractable DEs, with imagery illuminating both. Perhaps a lorenz attractor for the latter https://moodle.insa-toulouse.fr/pluginfile.php/35347/mod_label/intro/LorenzAttractor.png  — Preceding unsigned comment added by Rablankenship (talk • contribs) 02:54, 14 September 2014 (UTC)
thread_title:  Sections could benefit by adding images 

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thread_title:  External links modified 

message: This page redirects to Nonlinear_system#Nonlinear_differential_equations instead of Differential_equation#Non-linear_differential_equations. Is this an error? Jarble (talk) 05:10, 21 June 2018 (UTC)
replies: text: I think it’s an error and should be changed. Dolphin (t) 07:15, 21 June 2018 (UTC)
thread_title:  ''[[Nonlinear differential equation]]'' redirect page 

message: This article mentions "the Sagnik's equation", but I can't find any mentions of this equation online. Does this equation actually exist? Jarble (talk) 05:54, 20 November 2018 (UTC)
replies: text: I have never heard of this. I am going to remove that redlink. – Tea2min (talk) 12:20, 20 November 2018 (UTC)
thread_title:  Is there such a thing as the "Sagnik's equation?" 

message: The current definition of Differential Equation "a mathematical equation that relates some function with its derivatives" is technically not correct. For instance, the very first example provided in the page, dy/dx=f(x), is not a differential equation according to this definition since it does not relate y to its derivative. 
That's why I had changed the definition  to "a mathematical equation where one or more derivatives of an unknown function are presents", which I think is more appropriate.
Amanfroi (talk) 17:25, 20 June 2019 (UTC)
replies: text: The example that you cite was incorrectly stated. I have fixed it. This is true that a formal definition, should be "a mathematical equation that relates some function with its derivatives and its variable(s); the unknown function, the variables or and the derivatives need not to appear all in the equation, although at least one derivative must be present". However such a formal definition would be confusing in the first sentence: The manual of style MOS:MATH#Article introduction recommend: . So, if a more detailed definition should be given, this should be in the body. I am not sure that it is really useful. D.Lazard (talk) 18:40, 20 June 2019 (UTC)
replies: text:  Not sure how you fixed the first example. It still does not fit the definition given. Since the formal definition you quote says "although at least one derivative must be present", just use that in a simplified definition: an equation where at least one derivative of an unknown function is present. Amanfroi (talk) 20:15, 20 June 2019 (UTC)
thread_title:  Definition of Differential Equation is not correct 

message: Just like ODE and PDE are defined with their own section, I think it would be appropriate to define Linear and Non-Linear equations in their own section. Right now the definition of a Linear DE is buried inside the definition of an ODE. But PDE can be linear too.
Amanfroi (talk) 17:28, 20 June 2019 (UTC)
replies: text: When one talks of "linear differential equation" most people think "linear ODE". A witness of this is that in the article Linear differential equation, only the ODE case is considered. Moreover, the theory of linear ODE is well developed and widely taught, while the theory of linear PDE is must less known. It could be said in the section on PDE's that linear PDE's have been considered, but this should require an article to be linked to. Apparently such an article does exists (Linear PDEs redirects to Partial differential equation). Nevertheless, I would not object to add a sentence about linear PDEs in the section on PDEs, if it can be either correctly linked or reliably sourced. D.Lazard (talk) 18:59, 20 June 2019 (UTC)
replies: text:  I respectfully disagree based on how an introductory class on differential equation is often taught. Usually one starts by talking about ODEs and PDEs, Linear and Non-linear, Homogeneous and Non-homogeneous (which could be added). Also, linear PDEs like the diffusion equation, the wave equation, and the Laplace equation, are all taught in an introductory differential equation class.
As a side note, please fix the definition of non-linear equation: "Non-linear differential equations are formed by the products of the unknown function and its derivatives are allowed and its degree is > 1" is not grammatical. It also does not consider non-linear terms like y^(1/2) or sin(y).  — Preceding unsigned comment added by Amanfroi (talk • contribs) 20:22, 20 June 2019 (UTC)

text: D.Lazard (talk) 22:18, 20 June 2019 (UTC)
thread_title:  Why not separate Linear Differential Equation definition from ODE definition? 

message: Why is it not allowed to mention some programs that are able to solve differential equations: Maple, Mathematica, SageMath, Xcas and ExpressionsinBar among others?
Asked by MacApps 25 April 2020  — Preceding unsigned comment added by MacApps (talk • contribs) 16:39, 25 April 2020 (UTC)
thread_title:  Some software can solve differential equations