f



Why can't I solve this ODE set?

I tried to use Mathematica to solve this OED set:
DSolve[{y''[r] + (1/r + 2 I p) y'[r] + (-2 h + 2/r - m^2/r^2 - p^2) y[r] == 
 2 a z[r], 
z''[r] + (1/r - 2 I p) z'[r] + (-2 h + 2/r - m^2/r^2 - p^2) z[r] == 
 2 a y[r]},{y,z}r] .
But as I input it, nothing works. Mathematica just give back the same equations to me. Interestingly, either of the 2 equations can be solved separately, including the other in its expression. I mean:
DSolve[y''[r] + (1/r + 2 I p) y'[r] + (-2 h + 2/r - m^2/r^2 - p^2) y[
     r] == 2 a z[r], y[r], r]
DSolve[z''[r] + (1/r - 2 I p) z'[r] + (-2 h + 2/r - m^2/r^2 - p^2) z[
      r] == 2 a y[r], z[r], r] /. y[r] -> % .
Would anybody please help me, or explain why this phenomenon occurs?

0
Neo
5/19/2014 6:04:56 AM
comp.soft-sys.math.mathematica 28821 articles. 0 followers. Follow

0 Replies
1323 Views

Similar Articles

[PageSpeed] 52

Reply:

Similar Artilces:

Why is equation set can't solve in Mathematica?
Hi, all. This problem is annoying This: Solve[{yx13b == (-dg sxa yx13a + Sqrt[-dg dx1 sxa^2 yx13a + dg px013a sxa^2 yx13a - dg hxa sxa^2 yx13a^2 - dg sxa vx13a yx13a^2])/(dg sxa), yx13b == (-dx3 sxb + px013b sxb - 2 dg sxb yx13a - Sqrt[ 4 dg sxb (-dg sxb - hxb sxb - vx13b) yx13a^2 + (-dx3 sxb + px013b sxb - 2 dg sxb yx13a)^2])/( 2 (dg sxb + hxb sxb + vx13b))}, {yx13a, yx13b}] can't solve. Why? Perhaps you didn't wait long enough... I didn't have the time or patience either. But, let's have a closer look. There are two equations f...

Can't do math. Can't read.
Can't do math. Can't read. We must be talking about Snit. LOL! ...

config.sys corrupted; can't fix; can't start windows 2000
The computer attempts to open windows 2000 pro and gets hung up with the message that winn config.sus is corrupted. I tried booting from the win 2000 cd-rom and then creating floppy boot disks. The computer won't recognize or run off of these. Rename the Config.sys file in the root directly to ConfigOLD.sys. See if the machine will boot without it for now. Any release of NT should be able to. If you work out for sure that the Config.sys file is faulty, you can go in with your text editor, and troubleshoot it. You will need the base knowledge to work in this file. Jerry G. ======== ...

why set-car! and set-cdr! can be propagated like regular functions while set! can't?
hi Why set-car and set-cdr can be propagated like regular functions while set! can't? I can't figure this one out. (I'm rewriting all my functions into using only set-car!) This is sorta funny. dillogimp@gmail.com wrote: > Why set-car and set-cdr can be propagated like regular functions while > set! can't? I can't figure this one out. (I'm rewriting all my > functions into using only set-car!) This is sorta funny. In ancient LISP there was a function called SET, which was just an ordinary function. Therefore, you had to quote its first argument: (SET (QU...

Can't "click through" Static Text even with 'HitTest' set to 'off'?
I've got a GUI with some static text labels that I created in an .m file using the uicontrol() function. I made sure upon creation to set 'HitTest' to 'off'. I can check the controls after the fact, and indeed they all have 'HitTest' set to 'off'. However, I have a ButtonDownFcn call for the entire figure (I'm trying to tell when the user clicks on a specific piece of static text, but the text controls are generated dynamicall). If the user clicks on the figure background, the function executes properly. However, when the static text controls ...

More Mathematica CAN'T do than CAN???
A few evenings ago I was speaking with a "learned mathematician" at the local university here. In the course of our wide-ranging talk, he stated that Mathematica is only capable of doing less than half the problems in mathematics today. I was floored at his assertion. I have only scratched the surface of all that Mathematica can do. There's tons more that it CAN'T do??? Your comments are welcome. Nicholas Kormanik A couple of comments. First, if I could do "only" half the problems in mathematics, which is probably an infinite number, I woul...

Solve can't solve
Hi all (Mathematica 6.0.0 Windows XP) I'm trying to solve this: Assuming[0 < p0 < 1 && 0 < p1 < 1 && 0 < p2 < 1 && 0 < p3 < 1 && 0 < tau0 < 1 && 0 < tau1 < 1 && 0 < tau2 < 1 && 0 < tau3 < 1, Solve[{p0 == 1 - (1 - tau0)^(n - 1) (1 - tau1)^n (1 - tau2)^n (1 - tau3)^n, p1 == 1 - (1 - tau0)^n (1 - tau1)^(n - 1) (1 - tau2)^n (1 - tau3)^ n , p2 == 1 - (1 - tau0)^n (1 - tau1)^n (1 - tau2)^(n - 1) (1 - tau3)^n, p3 == 1 - (1 - tau0)^n (1 - tau1)^n (1 -...

can't set axes/Image 'Position'
Hi all, I have an axes and an image in the axes. I am trying to set the axes "Position" property to align the axes (and, thus, the image) in the figure the way I want. But every time I set the Position property I just get a white bground instead of the image and no axes. my_axes = axes; set(gca,'Position',[50 50 500 500]); image('cdata',cdata,'cdatamapping','scaled'); If I leave the "set" line out, the image gets displayed (but with a default position which I don't like). I tried playing with units, etc, no luck. Does anyone have an i...

Can't Print, Can't Forward
Dear LN Experts, I have a simple Lotus Notes database containing a form with several fields but no subforms. In production, the application does not allow anyone to print documents created with the main form or to forward them via email. I have checked each field individually and confirmed that the form security setting allows printing and forwarding and I am at a loss to resolve the problem. Although I am a manager in the db, I myself am not allowed to print a document. The print option is grey in the file menu. If I create a new document, enter some data and save it,...

Mathematica can't solve simple system of equations
Assume I have two equations a[i]^x(a[i]^x+a[j]^x)^(1/x)-p[i], where i=1,2, i!=j (not equal), and all variables, {a,x,p} are strictly positive. Mathematica cannot give me the answer that I can work out by hand in less than a minute. I used both Solve and Reduce to solve for a[i], i=1,2. Please advise. Mukhtar Bekkali On 9/15/05 at 5:16 AM, mbekkali@gmail.com (Mukhtar Bekkali) wrote: >Assume I have two equations a[i]^x(a[i]^x+a[j]^x)^(1/x)-p[i], where >i=1,2, i!=j (not equal), and all variables, {a,x,p} are strictly >positive. Mathematica cannot give me the answer that I ...

Mathematica can't solve this equations and stuck my PC
Hi All, I need to solve below two equations using mathematica. x and y are variables all other parameters are constants. Below are the two equations I need to solve and find x and y in terms of other constants. (a1*Sin[x-b1] / (y^2+a2*y+a3*y*Cos[x-b1]+c1)^0.5) + (a4*Sin[x-b2] / (y^2+a5*y+a6*y*Cos[x-b2]+c2 )^0.5 )==0 ( 2*y+a2+a3*Cos[x-b1] / (y^2+a2*y+a3*y*Cos[x-b1]+c1) ^0.5 ) + (2*y + a5 + a6 * Cos[x-b1] / (y^2 + a5*y + a6 * y *Cos[x-b2] + c2)^0.5 ) == -2/ (1+a7*r^(y/a8)) Use Kernel->Interrupt/Abort Evaluation from menu of front-end so PC is not stuck. ...

NDSolve can't solve a complex ODE correctly?
Dear all, I have two coupled ordinary differential equations which satisfied by two functions, a(t) and az(t). It can be shown analitically that as t approaches infinity, a(t) approaches az(t). But the numerical solution given by Mathematica doesn't agree this. Here is my code: ----------------------- lam = 1; eqb = ((a'[t]/a[t])^2 + 2a'[t]*az'[t]/a[t]/az[t] == lam); eqaz = (3(a'[t]/a[t])^2 + 2(a''[t]/a[t] - (a'[t]/a[t])^2) == lam); sol = NDSolve[{eqb, eqaz, a[0] == 1, az[0] == .5, a'[0] == .6}, {a[t], az[t]}, {t, 0, 2000}, MaxSteps -> 200...

Why can't I set sys.ps1 to a unicode string?
More precisely, why does sys.ps1 not appear if I set it to a unicode string? This problem is hard for me to describe here because my newsreader is not properly unicode enabled, but here's the gist of it: Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29) [GCC 4.2.1 (Apple Inc. build 5646)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> First, let's make sure our encodings are set properly: >>> import sys >>> sys.stdin.encoding 'utf-8' >>> sys.std...

Why mathematica can't solve this non linear equation
Hi All, I need to solve below equation. My PC got stuck. Solve[{(\[Mu]0 Sin[t - t0])/Sqrt[ l2^2 + \[Mu]0 l2 Cos[t - t0] + \[Lambda]0] + (\[Mu]1 Sin[t - t1])/ Sqrt[l2^2 + \[Mu]1 l2 Cos[t - t1] + \[Lambda]1] == 0, (2 l2 + \[Beta]0 + \[Mu]0 Cos[t - t0])/Sqrt[ l2^2 + \[Mu]0 l2 Cos[t - t0] + \[Lambda]0] + ( 2 l2 + \[Beta]1 + \[Mu]1 Cos[t - t1])/Sqrt[ l2^2 + \[Mu]1 l2 Cos[t - t1] + \[Lambda]1] + 2/( 1 + V r^(l2/D0)) == 0}, {t, l2}] ...