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

Feb2313 09:24 AM
micromass

1 
30,123 
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 
138,363 
It is very well known that the result of varying some functional gives a differential equation which solutions...

Feb1311 04:24 PM
Heirot

0 
1,028 
Hi, I am trying to solve a problem using the central difference scheme in Matlab where there are two coupled diffusion...

Feb1211 08:49 PM
robby991

0 
899 
If y = f(x) , and ( dy / dx ) + ( y / ( sqrt(a+(x^2)) ) ) = 0
I knew its solution is y = { sqrt(a+(x^2))  x } ,...

Feb1211 04:21 AM
tinytim

8 
2,576 
Hi,
Can anyone please help me understand what spherical harmonics are and their applicability?

Feb1011 04:32 PM
AlephZero

2 
1,514 
dy/dx = (2/pi^(1/2))e^((x^2)) eq 1.17
My book makes a statement about the symmetry of the family of solutions...

Feb1011 01:03 PM
MurdocJensen

8 
1,949 
Hi,
well let me put the question a bit clear...my concern area is on ode and pde...my question is when you solve a...

Feb911 05:36 AM
chwala

3 
2,226 
I am trying to understand this article at Wikipedia on epidemic deterministic models...

Feb811 10:53 PM
madiha.sahar

2 
2,108 
Hi, I'm having problems with the following question.
We have: ψ : R2 → R2 , ψ(x, y) = (x − y − x(x2 + y2), y + x −...

Feb811 03:45 PM
1a12

0 
792 
Attempting Problem 1 of Arnold: ODEs, Ch. 1, section 2.2, it seems I'm not understanding something pretty basic about...

Feb411 06:19 PM
Rasalhague

2 
1,103 
Hi
I will be grateful if someone knows about the following and explain it for me please.
What is finite...

Feb411 11:37 AM
mfarooq52003

0 
1,281 
Dear all,
I have derived a set of differential equations. One is still missing and its left hand side is called f...

Feb411 10:28 AM
landau_rules

0 
754 
I'm reading Arnold: Ordinary Differential Equations, Chapter 1. In section 1.2, an integral curve was defined as the...

Feb411 07:10 AM
Rasalhague

2 
1,718 
I've tried to make sense of this conjecture but I can't wrap my head around it.
We've been learning about the...

Feb311 11:16 PM
fzero

15 
2,356 
Dear All,
I am trying to solve the following system of PDEs
\frac{\partial{A}}{\partial{t}}=...

Feb311 04:18 PM
jmk9

6 
1,991 
Hi!!
I have to solve the nonlinear equations of motion in the article (16) (17) (18).
I Trasform the system in a...

Feb311 04:09 PM
jacckko

7 
4,178 
Given the difference equation
a_{n+2}+A_n(\lambda)a_{n+1}+B_n(\lambda)a_n=0
where
...

Feb311 07:06 AM
intervoxel

0 
1,040 
I am trying to solve a problem (not homework, too old for that! lol!) which involves the time dependent schrodinger...

Feb211 09:18 AM
timthereaper

1 
1,150 
Hi Mathematicians,
I recently encountered this problem in maximization...
Maximize 1170X1 + 1110X2
Subject to
1. ...

Feb211 07:34 AM
chwala

2 
1,061 
The relevant equations:
(1) \dot{x} = v(x), x \in U
(2) \varphi = x0, t0 \in R x0\in U
Let x0 be...

Feb111 05:24 PM
Landau

3 
1,280 
Hi,
I am working out a heat transfer problem but i've to solve the Differential equation in order to keep going on...

Feb111 12:49 AM
DeltaČ

3 
1,306 
Hi,
I recently need to do some numerical simulation by Euler method to solve a PDE.
However, I noticed that there...

Jan3111 02:32 AM
patrick1990

2 
1,569 
Hi, In my research on I have a 3rd order ODE where a deferent unknown variable is present . Converting the 3rd order...

Jan3011 03:20 PM
oby7842

0 
1,016 
"One morning it began to snow very hard and continued snowing stadily throughout the day. A snowplow set out at...

Jan3011 10:53 AM
Xyius

8 
4,504 
That is the title to the problem I am stuck on. Here is what it says..
Consider the equation,
\frac{dy}{dx} +...

Jan2911 11:28 PM
Xyius

0 
1,640 
dv/dt=g(k/m)*v^2
i thought about all sorts of diff eq solving techniques
but nothing comes up to my mind
...

Jan2911 02:46 PM
HallsofIvy

4 
959 
In your own words, what exactly is the purpose of the Existence Uniqueness Theorem and why is it useful :surprised

Jan2911 02:35 PM
HallsofIvy

2 
1,616 
My apologies, this isn't appropriate for this part of the forum, I have since moved it to the HW help.

Jan2811 02:18 PM
ohgeecsea

0 
1,379 
Hello, i'm trying to proof the partial derivative definition , how do i proof it ??
@f/ @x = lim h>0 lim /...

Jan2811 05:29 AM
Jonnyquest

12 
1,962 
Hi guys! Attached is the differential equation that I want to solve both numerically and analytically, numerically...

Jan2711 08:22 PM
thavamaran

2 
1,118 
I already finished a undergraduate ODE course that uses Elementary Differential Equations and Boundary Value Problems...

Jan2711 12:24 PM
sampahmel

0 
800 
Hey I was wondering if you'll could help. I was told that this is a simple proof but have been working on it for ages...

Jan2611 02:43 PM
HallsofIvy

1 
954 
Hi Everyone,
Apologies if this is posted in the wrong place.
I am trying to produce numerical solutions for the...

Jan2511 10:37 AM
rs12345

0 
1,069 
If I have:
\frac{dA(t,z)}{dz}
is it possible to convert this to a differential in the form:
\frac{dI(t,z)}{dz}...

Jan2411 04:17 PM
n0_3sc

6 
898 
QUESTION:
Solve the separable differential equation
dy/dx = sqrt(4y+64), Initial Condition: y(4)=9,
and find the...

Jan2311 01:17 PM
alchal

2 
1,098 
Hello All,
Given the equation (2/y + y/x)dx + (3y/x + 2)dy
I am first asked to show the equation is not exact. To...

Jan2211 09:38 PM
sleventh

4 
1,439 
HI, I have solved the diffusion equation using the central difference scheme. Next, I would like to code this...

Jan2211 09:11 PM
robby991

2 
1,803 
Hi everyone,
I need help with this problem. I just can't get it:
Let a,b,c,d,e and f be vectors such that...

Jan2211 02:26 PM
SammyS

2 
1,108 
When considering the solution u(x,y) of the poisson equation
u_xx + u_yy = 1 for (x,y) in G
on a 2dimensional...

Jan2111 06:00 PM
Ric72

0 
1,296 
I'm french and my englis is bad sorry but i need help !
My exam :
In this part of the study, we considered the...

Jan2111 03:05 PM
HallsofIvy

1 
819 
\underbrace{d}_{dt} (\dot{x})^{2} = 2\ddot{x} ??? or is it just 2\dot{x} ?

Jan1911 02:20 PM
blueberrypies

5 
999 