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

Feb2313 09:24 AM
micromass

1 
29,394 
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 
135,835 
Consider the following differential equations with initial conditions at time $t_0$ specified:
\dot{x}_1 =...

Oct2013 09:14 PM
Only a Mirage

0 
402 
Hello,
Working through some reduction of order problems. I'm not sure about why the structure of a particular...

Oct1913 09:04 PM
Simon Bridge

3 
699 
Good day. I was wondering if you could help me solve this first order linear partial differential equation:
/ = /...

Oct1813 11:25 AM
berkeman

1 
411 
Something has been bothering me. I see a phrase like this:
Plugging our two roots into the general form of the...

Oct1713 02:44 PM
mesa

3 
1,041 
I ran into some formula:
^{a}_{0}∫J_{o}(kr) rdr= a/k J_{1}(ka)
How can this be true? What property was used?

Oct1613 08:22 PM
jasonRF

1 
1,105 
Helmholtz equation:##\nabla^2 u=ku## is the same form of ##\nabla^2 u=f##.
So is helmholtz equation a form of...

Oct1613 06:09 PM
yungman

7 
1,610 
Hi,
I'm trying to solve the flow profile inside an inhomogeneous porous material between two parallel moving plates...

Oct1613 05:07 PM
Chestermiller

14 
13,515 
http://i.imgur.com/03izT8l.png
Why is the math in the red box necessary? According to this definition, it isn't:
...

Oct1613 04:42 PM
dextercioby

6 
948 
So, I'm trying to solve 2nd order linear differential equations (series solutions near a singular point).
(lnx)y"...

Oct1613 10:58 AM
Gridvvk

2 
1,949 
Hi all,
If we have
H'(r)=r+\tau(r)H(r)
and
\tau(r)=k+(H(r)/r)^a
where

Oct1613 08:31 AM
urbanist

2 
582 
I know nothing about DEs, so this may be a silly question.
I'm given some time varying (x_t)_t and a constant r,...

Oct1313 06:18 PM
economicsnerd

3 
5,609 
How can I determine the isotherms(curves of constant temperature) of given Temperature field like
T = x^2 y^2 + 8y....

Oct1313 05:02 AM
mfb

5 
4,713 
When solving a differential equation for Bessel Functions, how do you know when to use the 1st kind or Neumann...

Oct1313 04:30 AM
SteamKing

1 
614 
I need to prove that the solution of this differential equation:
dx/dt = x3 + 2*x + sin3(2*pi*t)  2*sin(2*pi*t) +...

Oct1213 12:31 PM
pasmith

1 
1,290 
For possion equation $$u_{xx}+u_{yy}=f$$
I know the general five point scheme is in the form...

Oct1213 09:27 AM
AlephZero

1 
773 
When the rod is infinite or semiinfinite, I was taught to use Fourier transform.
But I don't know when should the...

Oct1213 06:00 AM
HAMJOOP

2 
1,128 
Consider the harmonic oscillator equation (with m=1),
x''+bx'+kx=0
where b≥0 and k>0. Identify the regions in the...

Oct1013 07:45 AM
jfizzix

1 
1,341 
Hello... My main problem is to find the Green's function of this pde:...

Oct1013 04:29 AM
andreasgeo

0 
767 
Hello,
I'm now working on a charge limiting system. I tried modeling it an easy way to be studied.
...

Oct913 05:37 PM
carb

4 
2,458 
I'm finding for an example s.t.
$$Δu=f , 0≤x≤1, 0≤y≤\frac{\pi}{2}$$
$$Δu=0, x>1 , 0≤y≤\frac{\pi}{2}$$
let take...

Oct913 02:12 PM
sigh1342

0 
556 
I was wondering if there is a generalization of the following (roughly stated) theorem to ndimensional systems:
...

Oct713 03:35 PM
Only a Mirage

1 
1,958 
Hi all,
I'd be very happy if you could help me solve a problem in my research.
I need to prove the following:
...

Oct513 06:34 PM
pasmith

8 
7,669 
i got a book on differential equations that says a shortcut to solving the general differential equation...

Oct513 06:28 PM
fzero

1 
670 
Can you guys help with this question? i don't even know where to begin! *Cries*
Thanks! I have a test tomorrow and...

Oct513 12:03 PM
epenguin

2 
652 
http://i.imgur.com/64ADMbk.png
Are they both correct? Would the first or second solution be preferred?

Oct413 08:27 AM
HallsofIvy

7 
4,306 
I can't seem to model this properly. This isn't an assignment, I'm just curious how this will go, lol.
So I have this...

Oct413 07:52 AM
Chestermiller

3 
1,168 
Not sure how this can be done. can anyone help?

Oct313 04:15 AM
SteamKing

3 
1,223 
The highlighted in yellow is a mistake, right? I might be going insane.
Where does the PI go?

Oct213 12:10 PM
Turion

3 
1,213 
I have a function Z = f(P,T)
and would like to calculate the partial differentials \left ( \frac{\partial...

Oct213 10:50 AM
Chestermiller

2 
853 
Hey I have a degree robotics and moved to theoretical physics so am still struggling to keep up with the mathematics....

Oct213 05:13 AM
blade86

4 
2,824 
If we have \frac{1}{X(x)} \frac{d^2 X}{dx^2}=κ^2, the literature is saying that the solution must be: e^(±iκx), but...

Sep2913 10:46 PM
LCKurtz

6 
1,784 
I have a question about deriving the Bessel function of the second kind with integer order. I understand that the...

Sep2913 10:32 PM
yungman

1 
812 
Hi all,
I'm asking a question about the number of the boundary conditions in highorder PDE. Say, we are solving...

Sep2913 10:28 AM
pasmith

1 
1,284 
Hello,
In my Differential Equations class we are learning about modelling with first order differential equations....

Sep2813 02:55 AM
UltrafastPED

3 
1,029 
what are teh differential equations associated to Riemann Hypothesis in this article ??
...

Sep2713 11:45 AM
lostcauses10x

1 
1,064 
So we just started finding general solutions for homogenous&linear twovariabled PDEs by using separation of variables...

Sep2713 08:42 AM
jasonRF

6 
1,947 
Should I just assume that any problems that involve integrating factor will always result in a perfect integral pair?...

Sep2613 02:40 PM
GreenAce92

3 
3,126 
I'm new here, hope it is the right place to ask the question.
The PDE question is ∂2u/∂x2+∂2u/∂y2=0
and...

Sep2413 09:11 PM
hbl2012

2 
2,370 
Hello,I need somebody to help me in Mathematica programm
I wrote code that works as a function which I can call when...

Sep2413 11:00 AM
Bill Simpson

4 
964 
Hi, hope this is a right place to ask this question. I work in the soil physics field and this problem has taken lots...

Sep2413 07:30 AM
Chestermiller

3 
884 