Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

Hi,

What is the reason/Why: 

 

Error, (in dsolve/numeric/bvp) unable to achieve requested accuracy of 0.1e-5 with maximum 128 point mesh (was able to get 0.66e-1), consider increasing `maxmesh` or using larger `abserr`

Thanks for the help :)

I'm trying to plot the direction field of the second order differential equation x''=x'-cos(x) using dfieldplot: 

> with(DEtools); with(plots);
> f1 := (x, y) options operator, arrow; diff(x(t), t)-cos(x(t)) end proc;
/ d \
(x, y) -> |--- x(t)| - cos(x(t))
\ dt /
> dfieldplot([diff(x(t), t) = y(t), diff(y(t), t) = f1(x(t), y(t))], [x(t), y(t)], t = -2 .. 2, x = -2 .. 2, y = -2 .. 2);
Error, (in DEtools/dfieldplot) cannot produce plot, non-autonomous DE(s) require initial conditions.
>

The error I'm getting says I need initial conditions, but I wasn't provided with any. Is there another way to plot this? Sorry if this is dumb question, but I've only ever plotted first order equations.

Does anyone has any maple worksheet that generate surface using the PDE method described in this article?  I am trying to learn this method but I am not familiar with the mathematics to do it although the paper gives some description of it.  I hope someone can demonstrate the procedure in Maple.  Thanks

http://www.researchgate.net/publication/259095177_Automatic_shape_optimisation_of_pharmaceutical_tablets_using_Partial_Differential_Equations/file/72e7e52a87ed129d4a.pdf

I need to maximize two multivariate objective functions (f(x1,y1,z1,t1) and g(x2,y2,z2,t2)) with inequality and nonnegativity constraints (x1, x2>0 and y1, z1, t1, y2, z2, t2 >=0). I am looking for parametric not numerical solutions.


What is the best way to find the solution to such a problem using maple?

Hi

I want to create a linearied model for a single or multi degree of freedom vibration system by MapleSim. i faced a lot of problem such as causalize ports, i search the user manual but i didn't find it useful. i attach a very simply one degree of freedom vibration system. i wondering if every one create a linearized model for it. my final goal is governing the equation and determine the natural frequency with nyquist plots. i have mapleSim 6.2 and Maple 17. Thanks

 

prob1.msim

When trying to solve a set of partial differential equations, I always get the following error. I don't know what it means. Can somebody help me?

 

I need to write a procedure that takes an integer N and a boolean function F as in14 as arguments, returns nothing, and plots a square N × N lattice of points, coloring the points (i, j) with F (i, j) true in red and the other ones blue. 

Thank you in advance. Any help with this would be apreciated. 

write down the mapple procedure that finds the shape operator plus
gauss and primative curvatores and determines the surface characteristic
of a parametically given surface

 

best regards, ty

Dear All, I need your help to plot the numerical solution. many thanks.

The variable t in [0,T], x in [0,1], b in [0,2].

Difference finie for waves equation is :

pde:=diff(u(x, y,t), t$2) = c^2*(diff(u(x, y,t),x$2)+diff(u(x,y,t),y$2));

i: according to x, j according to y, and k according to t.

u[i,j,k+1]=2*u[i,j,k]-u[i,j,k-1]+(c*dt/dx)^2*(u[i-1,j,k]-2*u[i,j,k]+u[i+1,j,k])+ (c*dt/dy)^2*(u[i,j-1,k]-2*u[i,j,k]+u[i,j+1,k])

 

Boundary condition: u(t=0)=1, diff(u(x,y,t),t=0)=0, and the normal derivative on the boundary of Omega =0.

How can solve this problem and plot the numerical solution.

 

 

 

I am trying to write a procedure that have the following input:  expr, xdata,ydata. [dependent variables list]

I want a procedure to calculate Rsquare following the method described in 

http://www.mapleprimes.com/questions/120014-How-To-Calculate-Coefficient-Of-Determination

 

But I want the proc to take any abitary function and be able to identify the  dependent variable...how can I approach it? what function can I use to match [dependent variable list] in expr??

 

Thanks

 

 

I have a question regarding maple reader.

 

It seems like in maple reader, one cannot interact with the output of the Explore function.... which mean I am forced to make my own component if I want to creat application for my co-worker to use..this is some what annoying.  Is there another way around?

 

please open the attached file in maple player and you will see the output created by Explore gives error message.  mapleplayer_test.mw

 

Download mapleplayer_test.mw

.  

Pls, I tried solving the system of PDE numerically.... When I did for just 1 plot, the graph was plotted easilyrunning.mw but When I varied some parameters its not coming out.... Also, its not bringing any error so I can't trace out my mistakes....Not_runnin.mw PLS HELP ME OUT with the multiple plots... Attached are my source codes links....

 

When using Maximize, is it possible to now what parameter settings that resulted in complex numbers?

KR Fredrik

 

Maximize(Eq1_new, {R_K*rho*`&sigma;_K`+R_S*`&sigma;_S` >= .38780613588076011954, r_K*rho*`&sigma;_K`+r_S*`&sigma;_S` >= .21290471165685214846, R_K*rho*`&sigma;_K`+R_S*`&sigma;_S` <= .38780613588076011954, r_K*rho*`&sigma;_K`+r_S*`&sigma;_S` <= .21290471165685214846});


Error, (in Optimization:-NLPSolve) complex value encountered


intsolve(int(f1(u)*(x-y), u = a .. b) = (12)*cos(x)+5*x^2-12, f1(x));I try to resolve the integral equation but i received all the time the followinf message error 

Error, (in intsolve) invalid input: rhs received {f1(x) = ?}, which is not valid for its 1st argument, expr
I try to use different form but i do not how to resolve the help center do not help to much.

I preciate any help thanks

 

Hi.

please, I need some code about stepsize adaptative Runge Kutta method ( any order ) or other methods.

Thanks

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