Hi,

How do you plot a list of values/an array into a surface?

E.g.

t = [seq(0+i*(2*evalf(Pi)*(1/10)), i = 0 .. 10)]

x:=[3,4,2*evalf(Pi), 7.83]:

y:=[2.5,4.3,6,2*evalf(Pi)+2]:

z:=[-2,0.3,1.5,evalf(Pi)]:

plot3d([x[i]*cos(t), x[i]*sin(t), y[i]*cos(t-z[i])],-10..10,-10..10);

Hello,

I use maple for the determination of the symbolic relations between the geometric relations on multibody system.

I would like to create a dll function for the functions that I have determined symbolically.

I have already a paper presenting : 
- the transformation Maple --> code C with the package with(CodeGeneration)
- and the transformation code C --> another software.

I would like to directly create a dll function from my maple function with using code C. Is it possible and how ?

Thanks a lot for your help.

Hi there,
I have the following set of equation which I want to solve using Maple's dsolve command:

d[V(t)*C(t)]/dt = G - K *C(t)
dV(t)/dt = alpha - beta

where V is the volume, C is the concentration, and t is the time variable. G, K, alpha and beta are constant parameters of the problem.

The solution for V(t) is easy to find operating the second equation:
V(t) = V_0 + (alpha - beta)*t

But solving for C(t) is a bit harder.

I would like Maple to solve the system, but the result I get does not really make sense to me. My attempt is this: Maple_artificial_kidney.mw

Any thoughts about how to introduce the equations successfully?

Thank you,
jon

Hello everybody,

I am working on a somewhat complicated analytical problem, which includes the evaluation of the following (finite and singularity free) double integral (the stated numerical parameters may vary):

There are no unevaluated variables inside (all the e's are real exp()s). However, when putting it through evalf(), Maple returns it (after calculating for some time) unevaluated. I have no idea why, as a simple box sum should succeed.

Any input would be appreciated. Best regards,

  K. Reuther

P.S.: Raw expression for further deliberations

Int(exp(18.1818*(Int((0.579160e-1*sqrt(x)*Ei(1., 0.500000e-4*x)+(1072.23*(.999950-1.*exp(-0.500000e-4*x)))/sqrt(x))/sqrt(x), x = 1. .. eta))-9.10000*eta)/eta, eta = 1. .. 100.)

Hello,

we have a "little" Multibody Dynamics Project in our University. We try to compute a system with 4 DOF with Lagrange. The problem is that in the end our dsolve give us an error. We checked the whole system like 5 times and searched only for the dsolve problem over 6 hours.

Error from dsolve:

"Error, (in DEtools/convertsys) numeric exception: division by zero"

This error shouldnt be possible because we have no divisions at all in our system or somekind of inifity though arctan or what ever.

Any help would be perfekt.

Thanks a lot

Wackeraf

MultibodyDynamics_Gruppe_aktuell_V3.mw

Hallo. I'm solving a initial value problem for system of 7 ODE:

dsn := dsolve({expand(maineq[1, 1]), expand(maineq[1, 2]), expand(maineq[1, 3]), expand(maineq[1, 4]), expand(maineq[1, 5]), expand(maineq[1, 6]), expand(maineq[1, 7]), T(0) = .5, u(0) = u0, Y[1](0) = .8, Y[2](0) = .2, Y[3](0) = 0, Y[4](0) = 0, Y[5](0) = 0}, numeric, method = lsode[backfull])

Is there easy way how to plot result?

Is there a way with Maple 18 to place a bracket as shown below to contain two DE's? I am not trying to solve them. Only for note-taking purposes. If there is can you please share how to do it?

How to solve the equation
2^(sin(x)^4-cos(x)^2)-2^(cos(x)^4-sin(x)^2) = cos(2*x)
symbolically? The solve command produces a weird answer. Evalfing all its values, one sees
0.7853981634, -0.7853981634, 2.356194490, -2.356194490,

1.570796327 - 1.031718534 I, -1.570796327 + 1.031718534 I,

1.570796327 + 1.031718534 I, -1.570796327 - 1.031718534 I,

0.7853981634, -0.7853981634, 2.356194490, -2.356194490,

1.570796327 - 1.031718534 I, -1.570796327 + 1.031718534 I,

1.570796327 + 1.031718534 I, -1.570796327 - 1.031718534 I

The identify command
interprets the real solutions on -Pi..Pi as -3*Pi/4, -Pi/4, Pi/4, 3*Pi/4
(for example,
identify(2.356194490);

3*Pi/4 ).
Is it possible to obtain these with Maple in a simpler way?

PS. Mathematica 10 does the job.

PPS. So does even Mathematica 7.

Hello people in mapleprimes,

I have a question of labels of equations.

For example, suppose that there is a following description in a worksheet.

>2*x+y=5;

  2*x+y=5   (1)

>3*x+y=6;

  3*x+y=6   (2)

>solve({(1),(2)},{x,y});

 {x=1,y=3}          (3)

subs((3),100+x+100*y)

    400   

And, when I moved (2) to the next to (1) with dragging, and then, clicked !!! to execute it, then the worksheet 

changes as follows, which is wrong as accompanying ??

>2*x+y=5;3*x+y=6;

  2*x+y=5

 3*x+y=6   (1)

>solve({(1),??},{x,y})

{x = x, y = -3*x+6}          (2)

>subs({(1),??},100*x+100*y)

-200*x+600

Do you know some good way for ?? not to appear in the above sitiation.

I will appreciate when you tell me some measures about this.

Best wishes.

taro

Hi 

I'm having a problem with the statements inside a for-loop somehow being read in a different way than outside the loop. 

I've defined some functions earlier, and then I need to perform an integration using these functions, while I change one variable a little for each loop of the for-loop. 

The problem is that IN the for-loop, I get the same value from my integration for all loops. But when I execute the exsact same code OUTSIDE of the loop, I get the correct values, which are changing whenever i change the one variable. 

Here is the loop:

for i from 0 to 42 do

rotorshift := evalf[6](2*((1/180)* i *Pi*((1/2)*Ø[gap]))/N[m]-1/2*(tau[p]-tau[s]));

PMmmf_func := x-> proc (x) if type(x-rotorshift, nonnegative) then if type(trunc((x-rotorshift)/tau[p]), odd) = true then -H[c]*l[m] else H[c]*l[m] end if else if type(trunc((x-rotorshift)/tau[p]), odd) = true then H[c]*l[m] else -H[c]*l[m] end if end if end proc

B[g] := proc (x) -> 1000*mu[0]*(PMmmf_func(x)+MMF_func(x))/d[eff, stator](x) end proc;

Flux(i+1) := (int(B[g](x), 0 .. tau[s])+int(B[g](x), 3*tau[s] .. 4*tau[s])+int(B[g](x), 6*tau[s] .. 7*tau[s])+int(B[g](x), 9*tau[s] .. 10*tau[s]))*10^(-3)*L[ro];

end do;

And for all the values in the "Flux" vector, I get the same value. But when I remove the loop, and change the value of i manually, I get the correct (changing) values of flux!! 

Any ideas why this may be? This is really dricing me nuts. I've spent the beter part of the day on this, and I just can't seem to find a workaround, much less a reason for this behaviour.

many thanks!

I have generated an 8x8 Jacobian, containing a few variables and several zeros as elements. I would like to translate this to LaTeX code. How can I first simplify what I have, to make it tractable?

Here is the Maple code:

eq_1 := Lambda-mu*S-(beta*(H+C+C1+C2)*S+tau*(T+C)*S)/(S+T+H+C+C1+C2+C1M+C2M);
eq_2 := (-beta*(H+C+C1+C2)*T+tau*(T+C)*S)/(S+T+H+C+C1+C2+C1M+C2M)-(mu+mu[T])*T;
eq_3 := (beta*(H+C+C1+C2)*S-tau*(T+C)*H)/(S+T+H+C+C1+C2+C1M+C2M)-(mu+mu[A])*H;
eq_4 := (beta*(H+C+C1+C2)*T+tau*(T+C)*H)/(S+T+H+C+C1+C2+C1M+C2M)-(mu+mu[T]+mu[A]+lambda[T])*C;
eq_5 := lambda[T]*C-(mu+mu[A]+rho[1]+eta[1])*C1;
eq_6 := rho[1]*C1-(mu+mu[A]+rho[2]+eta[2])*C2;
eq_7 := eta[1]*C1-(mu+rho[1]+gamma)*C1M;
eq_8 := eta[2]*C2+rho[1]*C1M-(mu+rho[2]+gamma*rho[1]/(rho[1]+rho[2]))*C2M;
J := VectorCalculus:-Jacobian([eq_1, eq_2, eq_3, eq_4, eq_5, eq_6, eq_7, eq_8], [S, T, H, C, C1, C2, C1M, C2M]);

JQDFE := eval(J, [S = Lambda/(beta-mu[A]), T = 0, H = Lambda*(beta/(mu+mu[A])-1)/(beta-mu[A]), C = 0, C1 = 0, C2 = 0, C1M = 0, C2M = 0]);

Thanks.

Hi,

I am trying to interpolate a set of arbitrary numbers including real ones like Pi and plot them using ArrayInterpolate. This does not work. Is there a simple way around this?

Thank you.

Hi,

I use the VectorCalculus package to calcutate derivative formula for geometric functions, and met difficulity simplifying the result expression.

For example, I define some vectors P, S, V like below:

P:=<Px, Py, Pz>, S:=<Sx, Sy, Sz>, V:=<Vx, Vy, Vz>

then define an intermediate variable Q:=P - S,

then define a function d:= sqrt(DotProduct(Q, Q)-(DotProuct(Q,V))^2)

by calculating the function's derivative w.r.t Px I got a very complex result expression:

dpx:=1/2 * (2Px - 2Sx - 2 ( (Px - Sx) Vx + (Py - Sy) Vy + (Pz - Sz)Vz )Vx ) / (sqrt( (Px-Sx)^2 + (Py-Sy)^2 + (Pz-Sz)^2 - .....)

Apparently this expression can be simplified by substituting its sub-expression with pre-defined variables like Q and d.

I know I can use subs, eval, and subsalg to do it manually:

subs(1/(sqrt( (Px-Sx)^2 + (Py-Sy)^2 + (Pz-Sz)^2 - .....) = 1/dv, dfdpx)

subs((Px - Sx) Vx + (Py - Sy) Vy + (Pz - Sz)Vz = dotproduct_q_v, dfdpx)

and I can get a simplified expression like this:

(qx-dotproduct_q_v*vx)/d

But it's like my brain does the simplification first, and Maple only does the text substitution for me.

Is there any way to do it automatically?

Thanks,

-Kai

Hi i 2 questions. all pertaining to solving a systems of equations mod 2

First if i have a large set of equations, 11^3 equations in 11 unknowns and i want maple to give me ALL solutions mod 2 how can i do that? Maples msolve is loosing solutions.

Second suppose i want all unique solutions that say 6 of the variables can have but dont care what the solution to the other variables are as long as it is a solution. 

mini example:

say x=1,y=1,z=1 is a solution as well as x=1,y=1,z=0, i just want to know about x=1,y=1.

I have produded a 3D plot where I have used the graphic's lighting->user GUI to set the light color, direction, and ambient lighting to my liking.

I would like to save the lighting parameters so that I can reproduce the identical lighting in other plots.  I see no way of reading off the lighting parameters from the GUI.  I tried to "lprint(myplot)" to see if it contains that information but apparently it doesn't.

So my question is: Is there a way to retrieve the lighting parameters from a 3D plot?

--

Rouben Rostamian