handling exact solution from solve vs numerical solution from fsolve for same equation
hello; I am asking for the difference between > Digits:=200; > > eq:=-x^3+6*x^2-6*x-1: > fsolve(eq=0,x)[1]; > > solve(eq=0,x)[1]; > evalf(%); The result of evalf(%) above contains a complex part. No matter how large I make Digits to be. the result of fsolve contains only real part. The question is, would you consider this equation to have complex or real roots? thanks, Nasser In article <rXV3f.2604$tV6.1659@newssvr27.news.prodigy.net>, Nasser Abbasi <nma@12000.org> wrote: |>I am asking for the difference between ...

numerical solution of equation
I'm starting with Matlab and I don't know what to do to solve numerically x+e*sin(x)=omega*t where e, omega and t are calculated earlier in the program. Many thanks, tania In article <eefb68a.-1@webx.raydaftYaTP>, Tania <tania.re@wanadoo.fr> wrote: > I'm starting with Matlab and I don't know what to do to solve > numerically > > x+e*sin(x)=omega*t > > where e, omega and t are calculated earlier in the program. > > Many thanks, > > tania ------ Hello Tania, Do you have the Symbolic Math Toolbox? If so, try that with 'so...

How to get a numeric solution?
Hi! I've done an integration like this: >> int(((x^3)/(sqrt(x^2+1))),0,1) ans = -1/3*2^(1/2)+2/3 How do I get the numeric solution of this answer? I want an answer like this: 1.12345 instead of the exact solution. In the old version of MatLab on my school, I could do: numeric(ans), but this doesn't seem to work in version 7. Any help on this, folks? - Jan Rune Bj�rkelo - Jan Rune wrote: > Hi! > > I've done an integration like this: > > >>>int(((x^3)/(sqrt(x^2+1))),0,1) > > > ans = > > -1/3*2^(1/2)+2/3 > > > H...

get solution manuals, solution manual, solutions
These are part of our solutions not shown here , if the solution you want isn't in the list, do not give up, just contact us and we will find it to you email: lsms9[at] yahoo.com it's ls...@yahoo.com we have a lot of solutions manual over 700 solutions manual solution manual Math solution manual physics solution manual Calculus solution manual Dynamics solution manual mechanics solution manual electromagnetics solution manual Thermodynamics solution manual Circuits =2E. =2E. in low cast price .. Are you looking for solution manuals, solution manual, solutions I have solution m...

Numerical solution of a differential equation
Halloechen! I have the following DE: (r(t)-diff(r(t),t,t))^2 + (diff(r(t),t))^2 = 0. I want to solve this numerically. But every time I call dsolve I get the following error message: dsolve((r(t)-diff(r(t),t,t))^2+(diff(r(t),t))^2,r(t),numeric); Error, (in DEtools/convertsys) unable to convert to an explicit first-order system How can I solve the equation? Tschoe, Torsten. -- Torsten Bronger, aquisgrana, europa vetus On Sat, 7 Feb 2004, Torsten Bronger wrote: > (r(t)-diff(r(t),t,t))^2 + (diff(r(t),t))^2 = 0. > I want to solve this numerically. But every ti...

numerical solution of schrodinger equation
please describe the details of shooting method to solve schrodinger equation for an electron confined in a 1D infinite-Quantum well with width d.thank youe very much. Define vector x first, with length n and solve for y(x).Set y(1)=0;y(2)=1; and vary E until you obtain y(n)==0 or abs(y(n))<1e-6. Simply "integrate" the SE to obtain y(3) from y(2) and y(1) and so on. But you better use FEMLAB if you have that. /Per reza mohseni wrote: > > > please describe the details of shooting method to solve schrodinger > equation for an electron confined in a 1D infinite-Qu...

numerical solution for cubic equation
hello, I am now trying to solve a cubic equation like this: Z^3 + A*Z^2 +B*Z +C = 0 while A, B and C have some value. I want to solve the equation. but when I use the command: solve('Z^3 + A*Z^2 +B*Z +C = 0','Z') it only gives out simbolic solution, while i need the numerical solution. Is there anyway to get the numerical solution? thanks Done/ roots.m will help Zhuoyang Lian wrote: > > > hello, I am now trying to solve a cubic equation like this: > Z^3 + A*Z^2 +B*Z +C = 0 > while A, B and C have some value. I want to solve the equation. but > when I use the...

Numerical solution of quadratic equations set.
Dear MathGroup experts! I've got a system of quadratic equations with many (57) variables. Number of equations is less (38), so there may be an infinite set of solutions. Also I've got an aproximate solution that gives a good discrepancy. I want Mathematica to find some solution or/and improve the existing one. I'm interested in real (not complex) solutions. Here's what I've tried with no result: NSolve[eq == 0, var] - gives no solutions. FindInstance[eq==0,var,Reals] - gives no solutions. FindRoot[] says that there's not enough equations (yes, ...

How can I get the equation with numerical parameters ?
I have a equation like this a*x1 +b*x2 (a,b are all symbolic values) and I assigned the numerical value to a,b(e.g. a=0.5,b=0.6),and wish to get an equation like this: 0.5*x1 + 0.6*x2 Because I wish to write the equation above into a file, so I want to know how can I get the string forms like this: '0.5*x1 + 0.6*x2' Is there any simple way to do it ? Thanks in advance ! workaholic wrote: > I have a equation like this > > a*x1 +b*x2 (a,b are all symbolic values) > > and I assigned the numerical value to a,b(e.g. a=0.5,b=0.6),and wish > to get an equation li...

how to obtain the non-zero solution of the equation?
Hi all, I want to solve x for y=(e^x-x-1)/e^x-1 however, syms x y solve('x-y/(e^y-1)','y') ans = 0 but with the following online equation solver, i'm able to obtain the solution I want http://www.hostsrv.com/webmab/app1/MSP/quickmath/02/pageGenerate?site=quickmath&s1=equations&s2=solve&s3=basic It is free!!! But matlab is not! atemporal atemporal wrote: > I want to solve x for y=(e^x-x-1)/e^x-1 > however, > syms x y > solve('x-y/(e^y-1)','y') > ans = > 0 What do the two equations have to do with each other? If y=(...

Multiple Equation Solver
Hello everybody! I have written a small program witch solves a few equations with the multiple equation solver. The code is below: << { 'equation 1' 'equation 2'.... 'equation 10'} 'EQ' STO MINIT MSOLVR >> Program works really fine but when I exit from the ME-Solver a lot of variables (20 more or less) have been created (logically). This is the question: is it possible that these variables don't appear after the programn ends or stops? would be a solution to create a lib? Any ideas? Thx. "Marky" <cedecatalogueitor@ya.com...

Re: Numerical solution of differential equation
Dear Arturas, Many thanks for your kindness. Yes it is the classical Skyrmion. I know your papers on Skyrmions. It is surely nice that an expert can share his codes. Best regards, susy ...

transfer hp48 solver equations to hp49?
I call myself doing a search but could not find the information required. I wrote a lot of solver equations while in college with my hp48sx. I saved all these files since 1993 The files were saved as text so I could read them. I copied one of these directories with subdirectories and solver equations to my hp49.via an SD card. The file copied as text but I am not able to store the file as a directory structure. I created a directory and a solver equation in the hp49 and transferred it to the SD card. I viewed this with MS notepad and it appears unreadable as text. HPHP49-X=E2=80=93*=C3=B0=7F ...

Numerical solution of a third order equation
I tried the following program: a = 3; b = 2 ; c = solve('a*x^2+b*x^3-5=0') ; all I get is a symbolic solution. How can I obtain a numerical solution to such equations? Please help! do you really need Matlab to solve a 3rd order equation?!? anyway, the dumbest way c = double(solve([num2str(a),'*x^2+',num2str(b),'*x^3-5=0'])); Utzli Gutzli wrote: > > > I tried the following program: > > a = 3; > b = 2 ; > c = solve('a*x^2+b*x^3-5=0') ; > > all I get is a symbolic solution. > How can I obtain a numerical solution to suc...

Analytic Solution != Numerical Solution
Dear Group members, I ran into a case where Mathematica Solve yields different solutions depending on whether I solve it analytically (and then plug in some numbers) or numerically. I'm solving an algebraic equation, with some square roots. Mathematica does NOT complain about branch cut or anything else when solving the problem analytically. Based on physical reasoning that created the equation in the 1st place the purely numerical solution is the correct one. I attached a 3-line pdf version of the notebook that demonstrates this issue. Thank you for any suggestions! https://docs.goo...

Re: Numerical solution of differential equation with boundary
It does not work for bc F[10^-5] == Pi Having searched using google for some time, I found a solution as follows: \[Epsilon] = 10^-10; fSky[sl_?NumericQ] := NDSolve[{(1/4 r^2 + 2 Sin[F[r]]^2) F''[r] + 1/2 r F'[r] + Sin[2 F[r]] ( F'[r])^2 - 1/4 Sin[2 F[r]] - 1/(r)^2 Sin[F[r]]^2 Sin[2 F[r]] == 0, F[\[Epsilon]] == \[Pi], F'[\[Epsilon]] == sl}, F, {r, \[Epsilon], 1000}] fSky2[sl_?NumericQ] := With[{f = fSky[sl][[1, 1, 2]]}, f[f[[1, 1, 2]]]] Plot[fSky2[sl], {sl, -5.468, -5.469}] Plot[Evaluate[F[r] /. fSky[sl /. sl -> -5.46877516]], {r, 0., 10}, PlotRange ...

how to get all solutions of linear equations with deficient rank
I 've tried linsolve([1 1;2 2],[1;2]) and got Warning: System is rank deficient. Solution is not unique. > In C:\MATLAB6p5\toolbox\symbolic\@sym\mldivide.m at line 38 In C:\MATLAB6p5\toolbox\symbolic\linsolve.m at line 8 ans = [ 1] [ 0] my question is how to compute all solutions of the eqs. sangbo wrote: > > > I 've tried linsolve([1 1;2 2],[1;2]) > and got Warning: System is rank deficient. Solution is not unique. >> In C:\MATLAB6p5\toolbox\symbolic\@sym\mldivide.m at line 38 > In C:\MATLAB6p5\toolbox\symbolic\linsolve.m at line 8 > > ans = > &...

numerical solution to a set of equations with hypergeometric function
Hi, i ran into some trouble solving the following set of equations http://imageshack.us/photo/my-images/337/gleichungen.jpg/ for N and M, all other variables are known. I think the problem lies within the F- function. It's supposed to be the hypergeometric function. I used FindRoot and the hypergeometric2f1regularized command at first, but all i got were some errors. When i tried to solve it with the integral representation and the power series of the function I still didn't get any results. If i insert all the values it does look like this: FindRoot[{((0.5*0.5 + 0.5*0.5)...

Re: Numerical solution of differential equation with boundary
susy wrote: > Hallo, > > I need to solve the following differential equation: > > (1/4 r^2 + 2 Sin[F[r]]^2) F''[r] + 1/2 r F'[r] + > Sin[2 F[r]] (F'[r])^2 - 1/4 Sin[2 F[r]] - (Sin[F[r]]^2 Sin[2 F[r]])/r^2 == 0 > > with boundary values: > F[0]==Pi, F[Infinity]==0. > > I tried NDSolve, but failed to get a solution. > How can I solve that equation? > > Best regards, > susy > I had some luck by changing to a finite interval via r->1/(1+r). But I still needed to scoot in a bit from the origin (correspon...

numerical solution of differetial equation of second order
Diffusion equation of one dimension : D^2y/Dx^2+y+Q(x)=0 Q(x) is a known number that can be calculated. Dear jianbing! > Diffusion equation of one dimension : > D^2y/Dx^2+y+Q(x)=0 > Q(x) is a known number that can be calculated. Do you have a question? Curious, Jan > Diffusion equation of one dimension : > > D^2y/Dx^2+y+Q(x)=0 > > Q(x) is a known number that can be calculated. Setting y1=y, y2=dy/dx, rewrite your equation as dy1/dx = y2 dy2/dx = -y1 - Q(x) and solve using ODE45 if it's an initial value problem or BVP4C if it&...

numerical solutions to two non algebraic equations.
Hello, I am trying to get the decimal expansion of solution to sin(x)-exp(-x)=0 around pi, its about 3.093639, and the decimal expansion of solution to x^(9^x)=9, its about 1.179. Thank you for your time and consideration. Bob. FindRoot[Sin[x]-Exp[-x]==0,{x,3}] {x -> 3.0963639324106462} FindRoot[x^(9^x)==9,{x,1}] {x -> 1.1790679941305466} Bob Hanlon > > From: "Robert G. Wilson v" <rgwv@rgwv.com> > Date: 2005/03/26 Sat AM 02:39:22 EST > To: mathgroup@smc.vnet.net > Subject: numerical solutions to two non algebraic equa...

Numerical Solution to system of partial differential equations
I am trying to solve a system of 3 coupled partial differential equations numerically using pdepe, the built-in matlab pde solver. It is giving some results that I find unphysical and I'm wondering if pdepe was built for such a system. Let "w" be the wave action density. "v_x" be the zonally averaged flow in the "x", or east-west, direction. And "k_y" the wave number corresponding to the vertical, "y", or north-south, component of the Rossby waves. Let w_t denote the partial derivative with respect to time, w_tt the second partial derivat...

numerical solution to a set of non-liner equations
Hi, Maple experts, I have two non-linear equations as follows: tau := 1 - (1-p)^(1/9); tau := 2(1-2*p)/ ((1-2*p)*33 + p*32*(1-(2*p)^5)); p and tau are both on the interval of (0,1), and we know there is a unique (p, tau) pair solution. Which Maple function/command can be used to solve the above two equations? I have tried "solve" but it doesn't work. Many thanks in advance for your help! Xinhua In article <ctmr3f$b1g$1@rumours.uwaterloo.ca>, Xinhua Ling <x2ling@bbcr.uwaterloo.ca> wrote: |>I have two non-linear equations as follow...

Numerical solution of differential equation with boundary values
Hallo, I need to solve the following differential equation: (1/4 r^2 + 2 Sin[F[r]]^2) F''[r] + 1/2 r F'[r] + Sin[2 F[r]] (F'[r])^2 - 1/4 Sin[2 F[r]] - (Sin[F[r]]^2 Sin[2 F[r]])/r^2 == 0 with boundary values: F[0]==Pi, F[Infinity]==0. I tried NDSolve, but failed to get a solution. How can I solve that equation? Best regards, susy I suppose some insight into the behavior of F[r] is required to avoid singularities.The following works for different BC. NDSolve[{1/4 r^2 + 2 Sin[F[r]]^2 F''[r] + 1/2 r F'[r] + Sin[2 F[r]] F'[r]^2 - ...