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10 votes
5 answers
7k views

Are there examples of third-(or higher)-order linear differential equations in physics or applied mathematics?

The classical second-order linear ordinary differential equation is that named after Sturm and Liouville: formally, \begin{equation} (pu')'=ru. \end{equation} It arises naturally in many physical ...
Stromael's user avatar
  • 1,442
10 votes
2 answers
666 views

Physical meaning of linear ODE $xy''+2y' + \lambda^2 x y = 0$

As reported by Wikipedia - Sinc function, $y(x)=\lambda \operatorname{sinc}(\lambda x)$ is a solution of the linear ordinary differential equation $$x \frac{d^2 y}{d x^2} + 2 \frac{d y}{d x} + \lambda^...
Mark's user avatar
  • 7,880
10 votes
4 answers
2k views

What is the physical meaning of fractional calculus?

What is the physical meaning of the fractional integral and fractional derivative? And many researchers deal with the fractional boundary value problems, and what is the physical background? What ...
user70746's user avatar
  • 111
8 votes
2 answers
2k views

Differential vs difference equations in mathematical modeling

I'm reading a little about mathematical modeling and I've seen some population models based on differential equations. I've also seen some (not many) that can support both difference and differential ...
Hiperion's user avatar
  • 1,773
6 votes
2 answers
259 views

Dynamical system defined with a non-abelian group

Soft question. I'm taking an introductory mini-course in dynamical systems, and the professor defined a continuous dynamical system in a topological space $M $ (or metric space, smooth manifold, or ...
Ivo Terek's user avatar
  • 78.4k
6 votes
1 answer
2k views

Background for studying and understanding Stochastic differential equations

Assume I have back ground of the following knowledge based on the textbook as : ODE : ODE by Tenenbaum Baby probability : Ross 's baby probability Baby real anlysis : Bartle's introduction to real ...
Peter's user avatar
  • 1,975
6 votes
7 answers
10k views

How to prove $A\cos(\omega t-\phi)$ = $a\cos(\omega t)$ + $b\sin(\omega t)$ using $e^{i\theta}$?

I want to show that $A\cos\left(\omega t-\phi\right)$ = $a\cos\left(\omega t\right)$ + $b\sin\left(\omega t\right)$ First I verified for myself through the angle addition proof that: $$ \cos\left(\...
Anthony O's user avatar
  • 363
5 votes
1 answer
686 views

Solving Kepler's second law

Kepler's second law, about equal areas in equal times, is a differential equation: it gives velocity as a function of location. Where are the best expository accounts of the process of solving this ...
Michael Hardy's user avatar
4 votes
5 answers
757 views

Why - not how - do you solve Differential Equations? [closed]

I know HOW to mechanically solve basic diff. equations. To recap, you start out with the derivative $\frac{dy}{dx}=...$ and you aim to find out y=... To do this, you separate the variables, and ...
JackOfAll's user avatar
  • 4,769
4 votes
3 answers
3k views

Modelling with exact differential equations?

I'm teaching some very elementary differential equations to engineering students, and their constant question to me is "What's the use of this?" or alternatively "Where would we use this?" Now, I'm ...
Alasdair's user avatar
  • 840
4 votes
1 answer
253 views

What mathematics topics pertain more towards applied mathematics?

I'm entering my second year of undergrad (majoring in mathematics), and I've found that I am really bad at Linear Algebra, but very good at Calculus and Differential Equations. I'm hoping to venture ...
Turra's user avatar
  • 141
4 votes
1 answer
1k views

Applications of First Order Differential Equations

Can I get help for this question please? Suppose that a tank containing a liquid is vented to the air at the top and has an outlet at the bottom through which the liquid can drain. It follows from ...
Harriet's user avatar
  • 95
4 votes
0 answers
121 views

Do repeated roots (and Real Jordan form) for ODE's come up in real world applications of ODE's

An equation like $y^{\prime \prime} + 2 y^{\prime} + y = 0$ has repeated roots: The characteristic polynomial is $r^2 + 2r + 1$ which has repeated roots $(-1,-1)$. Two basic solutions of the ODE are ...
Smithey's user avatar
  • 705
3 votes
1 answer
868 views

Time reversal in Robertson's chemical reaction

I am studying the behavior of the Robertson chemical reaction, $$\begin{array}{rl} \dot{x} &= -0.04 x + 10^4 y z\\ \dot{y} &= 0.04 x - 10^4 y z - 3 \times 10^7 y^2\\ \dot{z} &= 3 \times ...
emprice's user avatar
  • 179
3 votes
1 answer
219 views

Could there be exact solutions to the Lane-Emden equation for real n≥0 other than 0, 1, or 5?

This Astronomy SE answer says With a constant $k$ and the polytrop index $n$. This is a result of the solutions of the Lane-Emden equation $$\frac{1}{\xi^2} \frac{\mathrm{d}}{\mathrm{d}\xi} \left(\xi^...
uhoh's user avatar
  • 1,893

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