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.

The equation

x^7+14*x^4+35*x^3+14*x^2+7*x+88 = 0

has the unique real root

x = (1+sqrt(2))^(1/7)+(1-sqrt(2))^(1/7)-(3+2*sqrt(2))^(1/7)-(3-2*sqrt(2))^(1/7).

Here is its verification:

Is it possible to find that in Maple? I unsuccessfully tried the solve command with the explicit option.

I was required to purchase Maple 17 for my upcoming Calculus III course, and until now, I have been using my TI-Nspire CAS CX for all of my CAS needs.  I am going through various tutorials/labs in an effort to learn how to use the Maple 17 Software. As a part of this process, I am attempting to solve a system of equations and was told to use the following command:

>solve({2*x+3*y=7,5*x+8*y=9},{x,y}); 

in order to receive the answer 

{y=-17,x=29}.

Instead, I have received the following error message, which has no help attached to it through the help page.

solve({2*x+3*y = 7, 5*x+8*y = 9}, {x, y});
Warning, solving for expressions other than names or functions is not recommended.

I am hoping this has something to do with Mac vs. Windows software, and that it has a simple solution.  I would greatly appreciate any guidance!

There are two normals to a point on a curve.  How do I get the PlotPositionVector of Student[VectorCalculus] to point in the other direction. 

with(Student[VectorCalculus]:

R1:=PositionVector([p,p^2],polar[r,t]):

PlotPositionVector(-R1,p=1..2,normal=true,points=[1.5])

The normal vector points towards the insided of the curve.  Can I use PlotPositionVector to have it point the opposite way (towards the outside of the curve)?

restart:

ODE:=diff((-diff(u(y),y))^n,y)=A;

bcs:=D(u)(0)=0,u(h)=0;

dsolve({ODE,bcs});

             u(y) = 0

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

Pleas i want to do continued fractional expansion to transfer function G(s) with numerator and denomenator as a polynomial in Lplace operator s.

with my gratitude

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 will plot the following equation so that the horizontal axis in terms of omega and vertical axis in terms of a,but i can not do it,can i help me?

equation:

Hi ,

I would like to resolve the Kortweg and de Devries equation :

> KDV2:= diff( u(X,T), T)+ 6*u(X,T)*diff(u(X,T),X)+ diff(u(X,T),X$3);

I used pdsolve but I have a problem to enter the IBC :

I want

u(infinity, t) =0
u( -infinity, t )=0

u ( x, 0 ) = 1

So I did :

> SOL:=pdsolve(diff( u(X,T), T)+ 6*u(X,T)*diff(u(X,T),X)+ diff(u(X,T),X$3)=0,{u(-10, T) = 0, u(10, T) = 0, u(X, 0) =1},numeric,time=T,range=-10..10);

But it doesn't work.

( I remplace infinity by 10 because then I want the graphic representation of the solution )

Could you help me please ?  

Hi,

I am completely new to Maple (and this kind of software in general).

I am just on my first steps of learning...but I quickly noticed, that if I write Pi and hit enter, I do not get

the well-known greek Pi-symbol. I get an ordinary "p" as the result.

I checked the greek-palette...nearly all items in this palette are ordinary letters.

Does anyone have an idea whats wrong?

BTW: I don`t know if it could have to do with that, but I use a german windows 7 installation.

Thank you,

regards,

Kai

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

Hello,

restart:

F+(1/4)*(4*(-Lambda)^(3/2)*h*m^2-2*sqrt(-Lambda)*exp(Lambda*h^2*m^2)*h*m+sqrt(Pi)*erf(h*m*sqrt(-Lambda)))/(m^2*(-Lambda)^(3/2)) = 0;

how to solve this for m for real roots, where the rest are constants with Lambda>0.

Hi:

I have a curve(plot) in Maple and i should find the math equation for it,everybody can help me how to find it?