
Please post any and all homework or other textbookstyle problems in one of the Homework & Coursework Questions...

Feb2313 09:24 AM
micromass

1 
30,172 
My intent is to create a thread for people interested in Differential Equations. However, I will explicitly state that...

Jul312 07:18 PM
Luccas

95 
138,495 
Hello,
I watched a lecture by Leonard Susskind, in which he said that a differential is so short that when you...

Apr2914 09:49 AM
dauto

15 
998 
If a repeated integral can be expressed how an unique integral:
...

Apr2814 03:51 PM
Jhenrique

7 
384 
What are the applications of AdamsBashforthMoulton Method for O.D.E.'s in the real world? How we could utilize this...

Apr2814 01:08 PM
iwan89

5 
398 
I was thinking about some form of classify all kinds of equations and system of equations. And the better...

Apr2514 01:18 PM
micromass

6 
371 
Hello,
I have trouble solving the following differential equation.
I am trying to learn how to solve that form...

Apr2514 08:52 AM
vanhees71

3 
454 
Hi,
I'm an engineer who uses a lot of finiteelement software for doing multiphyics modeling. I've been learning a...

Apr2214 10:31 PM
the_wolfman

9 
481 
Hello I was recently working on a problem where I had to solve the differential equation in the title ( where y is a...

Apr2214 12:48 PM
the_wolfman

2 
305 
I would like to model rain hitting a surface and then running off of the surface. The surface would be a square, such...

Apr2114 07:07 AM
HallsofIvy

1 
457 
I'm having a hard time understanding Green's functions which have been introduced quite early on in the course, and...

Apr2014 12:49 AM
chipotleaway

2 
350 
I'm not sure if this is particularly important, but so far through my studies I've only encountered DE with two...

Apr2014 12:21 AM
micromass

2 
309 
For a system of linear differential equations with constant coefficients with known initial conditions an analytical...

Apr1914 10:26 AM
Mark44

1 
311 
I'm trying to analyze the following Ito stochastic differential equation:
$$dX_t = \X_t\dW_t$$
where X_t,...

Apr1814 06:57 PM
Only a Mirage

2 
339 
Hi everyone,
I'm taking the Differential Equations for the first time, and I want to know the most helpful textbook...

Apr1814 08:12 AM
Bill_K

2 
376 
When I multiply out the first line I end up with an extra (dA/dx)*(dσ/dx). Can someone please show me how i get from...

Apr1714 04:44 PM
Bill_K

1 
286 
In this video at around 9:00 , Carl Bender demonstrates a method of solving y''+a(x)y'+b(x)y=0.
...

Apr1714 09:28 AM
chipotleaway

2 
266 
Definition: ##f(x+k) = \exp(k \frac{d}{dx}) f(x)##
So I thought, how take advantage this definition? Maybe it be...

Apr1714 08:19 AM
Jhenrique

2 
329 
Hello I am trying to solve this ODE
dx/dt=(f(x)+g(t))^(1/2)
I have been recalling what I learn in my ODE...

Apr1614 02:16 PM
MathematicalPhysicist

8 
435 
I tryied make the convolution product between x² and x³ by ##\int_{ \infty}^{+ \infty} f(u) g(xu) du## and the...

Apr1414 06:20 PM
micromass

5 
377 
I have a differential equation to solve below on the motion of an object oscillating in water with a restoring force...

Apr1414 11:34 AM
the_wolfman

1 
314 
Hello, PF! As I was reading my PChem textbook, I noticed most thermodynamic equations involve partial derivatives,...

Apr1314 08:18 PM
Mark44

3 
362 
I know that the standard definition for a slope field is ##\frac{dy}{dx} = f(x, y)##, but and if the equation given is...

Apr1314 04:08 PM
HallsofIvy

1 
273 
f(x,y) = ln(9  x2  y2)
Domain I got:
(x, y) in R2 such that x2 + y2 < 9
How do I find the range from the...

Apr1214 12:09 PM
JC3187

6 
354 
Show that the explicit RungeKutta scheme
\begin{equation} \frac {y_{n+1} y_{n}}{h}= \frac{1}{2}
\end{equation}...

Apr1014 07:21 PM
rickyflair

2 
339 
If a system of firstorder ODEs like ##\frac{d\vec{r}}{dt}=A\vec{r}## have as solution ##\vec{r} = C_1 \exp(\lambda_1...

Apr1014 02:58 PM
Jhenrique

9 
552 
Hi All,
I am taking Dynamic Systems and Controls this semester for Mechanical Engineering. We are solving non...

Apr914 12:40 AM
MisterX

1 
390 
You can give me a good examples where ##\frac{\partial}{\partial x}## is different to ##\frac{d}{dx}## ?

Apr814 09:12 AM
Jhenrique

2 
378 
Hello
I am having some trouble understanding what the difference is between the reference solution and the "true"...

Apr714 07:36 AM
jjr

2 
444 
Hello guys, suppose we have an eigenvalue problem
\left\{
\begin{array}{ll}
u'' + λu = 0, ...

Apr214 10:44 AM
AlephZero

6 
521 
I realized that a PDE of 2nd order can written like: A:Hf+\vec{b}\cdot\vec{\nabla}f+cf=0
\begin{bmatrix} a_{11} &...

Apr114 09:22 PM
Jhenrique

0 
338 
Hi,
I am looking for a solution of
\frac{\partial\phi}{\partial t} =...

Apr114 06:50 AM
soni

0 
322 
Which the difference between diff equations of kind: \frac{dy}{dx} = \exp(x) \frac{dy}{dx} = 1/x
and diff equations...

Apr114 02:22 AM
Mark44

8 
401 
Hello, I have been trying to find an equation to represent the observed angular velocity of any object traveling in a...

Mar3114 08:50 PM
bendloewen

3 
425 
Hello,
I'm trying to analyze a system of elastically coupled oscillators, whose masses are all the same, using...

Mar3114 10:51 AM
Runei

1 
303 
Hello,
I am doing some physics and I end up with this PDE:
\frac{\partial q(x,y,t)}{\partial t} = (x^2 +...

Mar2814 02:51 PM
kosovtsov

4 
704 
How do we solve a system of coupled differential equations written below?
\frac{d^2}{dr^2}\left(
\begin{array}{c}...

Mar2714 11:04 PM
Ravi Mohan

2 
480 
Given a implicit ODE like F(x, y(x), y'(x), y''(x)) = 0, why your explicit form is y''(x) = f(x, y(x), y'(x))? Why a...

Mar2714 12:36 PM
micromass

4 
432 
If we have a constant coefficient second order homogeneous ODE, the way to solve this is to suppose a solution of the...

Mar2714 08:13 AM
quasar987

4 
404 
hello pf!
i am wondering if anyone here knows of a geometric, intuitive explanation for the laplace transform? if...

Mar2614 05:34 PM
micromass

3 
372 
I would like to learn this. Can someone teach me? The things like δy2/δ2x and solving for x and y. :rolleyes:

Mar2614 12:37 AM
z.js

10 
704 
I want to solve y''+y'+y=(sin(x))^2 and try to use
y=Ae^{ix} but then when I square it I get A^2 e^{2ix}
...

Mar2614 12:26 AM
lurflurf

1 
333 