Maple 2018 Questions and Posts

These are Posts and Questions associated with the product, Maple 2018

Hello there,

for academic purposes I need to solve a pretty complex and substantial non-linear equation system. Here you can have a look at the equations:

kompletter_nachbau_v0.mw

The MAPLE Statement "fsolve" is not working here, though there is no error message. I know, that I can provide a framework for each variable to help fsolve find a solution. But for my usage this is not an appropriate task, since I'd like to do some simulations and variations with the input parameters.

Is there a way, so I can find a solution to my equation system?

 

It would be possible to make some adjustments to my equations, e.g. reducing the complexity of the equations and increasing the number of equations at the same time, if needed.

I would appreciate any advice!

Thanks in advance!

In the worksheet below I produce a sequence of frames for an animation by distributing the task into several threads.  The result has strange artifacts as we see in the sample.  The artifacts vary randomly from run to run.  Am I doing something wrong?

restart;

kernelopts(version);

`Maple 2018.2, X86 64 LINUX, Oct 23 2018, Build ID 1356656`

kernelopts(numcpus);

4

Draw a simple picture:

frame := proc(t)
  plot(x^2 + t, x=-1..1, title=typeset("t = %1", t));
end proc:

Generate a sequence of pictures:

frames := Threads:-Seq(frame(t), t=0..1, 0.05):

Animate the sequence:

plots:-display([frames], insequence);

Download theads.mw

Hi all,

I have a data set (see .txt file attached) to be fit to the model function A*sin(B*x+C)+D. Calculating the parameters A, B, C, and D is easy enough, but is there a way to have Maple return their standard errors?

Data.txt

Hi,

I can’t perform the last command (GridPlot) on my worksheet

 

 

IRISdata.mw


 

 

How would I go about getting true or false returned on these propositions?
I have tried just about every eval and various syntax methods, but nothing has worked so far.

I know most can easilly be done by hand/thinking, but I'm sure Maple should have a way to do this as well.

∀n∈Z:2n>n+2   ,   ∃n∈Z:2|(3n+1)    ,   ∃k∈Z:∀n∈Z:n=kn   ,   ∃k∈Z:∀n∈Z:2|(n+k)   ,   ∀n∈Z:∀k∈Z:(n>k∨k≥n)

how i can solve the eqution by ritz methode codes?

verify(2*cos(phi)^2-1, cos(2*phi), equal); returns FAIL even though is a trig identify. Any ideas why?
 

Maple currently can't integrate things like sin(x)^n or cos(x)^n. These have antiderivative in terms of  hypergeometric functions.

Is there a technical reason why Maple at version 18 still can't integrate these? Will it be able to in next version?

int(cos(x)^k, x) 
int(sin(x)^k, x) 

fyi, These are the antiderivatives

Same problem for tan(x)^n....  I am asking because Maple is able to solve many ODE's but some results contains unevaluated integrals such as the above. 

 

When making this call to dsolve

 

restart;
ode:=diff(y(x),x)=1:
stopat(dsolve);
dsolve(ode,y(x));

Then in the debugger, I see that dsolve signature is

dsolve := proc(ODEs::{anything} := NULL, 
                {atomizenames::truefalse := true, build::truefalse := false, type::name := 'none'})

When typing print(ODEs) inside the debugger, it gives "diff(y(x),x)=1" which is correct.

But where is the second argument I passed to dsolve in the above call, which is "y(x)" gone?  I also do print(_nparams) inside the debugger and Maple returns 1 and not 2.

I expected to see 2 since I passed in two arguments to dsolve.

dsolve actually works without passing y(x), as follows

dsolve(ode);

And it seems Maple figure inside what is the dependent variable.

But my question is, is the second argument being thrown away before calling dsolve? If not, why it does not show in the debugger?   Is there some other pre-processing being done between the time the user calls dsolve() and the time the debugger is called?

 

 

 

i have two ode equations, when try to solve, i face this error
Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system
any comment or help to solve this? ( or any simplifying comments to solve) . thnx in advance

 

restart

A := 4263736263.736263:B := 11868131.86813187:C := 600146.5201465202:hr := 0.3e7:muz := 0.2632654643708247e-5:P:=1000:

1000

(1)

ode1 := diff(u(r), r, r)+(diff(u(r), r))/r-u(r)/r^2-B*(diff(w(r), r, r, r)+(diff(w(r), r, r))/r-(diff(w(r), r))/r^2)/A = 0;

diff(diff(u(r), r), r)+(diff(u(r), r))/r-u(r)/r^2-0.2783505155e-2*(diff(diff(diff(w(r), r), r), r))-0.2783505155e-2*(diff(diff(w(r), r), r))/r+0.2783505155e-2*(diff(w(r), r))/r^2 = 0

(2)

ode2 := C*(diff(w(r), r, r, r, r))+2*C*(diff(w(r), r, r, r))/r-(C/r^2+muz*hr^2)*(diff(w(r), r, r))+(C/r^3-muz*hr^2/r)*(diff(w(r), r))+muz*hr^2*w(r)/r^2-B*(diff(u(r), r, r, r))-2*B*(diff(u(r), r, r))/r+B*(diff(u(r), r))/r^2-B*u(r)/r^3 = P;

600146.5201465202*(diff(diff(diff(diff(w(r), r), r), r), r))+1200293.040*(diff(diff(diff(w(r), r), r), r))/r-(600146.5201465202/r^2+23693891.80)*(diff(diff(w(r), r), r))+(600146.5201465202/r^3-23693891.80/r)*(diff(w(r), r))+23693891.80*w(r)/r^2-11868131.86813187*(diff(diff(diff(u(r), r), r), r))-23736263.74*(diff(diff(u(r), r), r))/r+11868131.86813187*(diff(u(r), r))/r^2-11868131.86813187*u(r)/r^3 = 1000

(3)

ics := w(.2) = 0, (D(w))(.2) = 0, w(1) = 0, (D(w))(1) = 0, u(.2) = 0, u(1) = 0;

w(.2) = 0, (D(w))(.2) = 0, w(1) = 0, (D(w))(1) = 0, u(.2) = 0, u(1) = 0

(4)

dsolve({ode1,ode2} union {ics},{w(r),u(r)},numeric)

Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system

 

 

 

Download zzv.mw

Here is a simple procedure that works fine if entered using 1D Maple input
> Q:=proc(x)
sin(x)
end proc;
but if you use 2D math input
> q:=proc(x)
sin(x);

  end proc;

Error, unterminated procedure
    Typesetting:-mambiguous(qAssignTypesetting:-mambiguous(

      procApplyFunction(x) sinApplyFunction(x),

      Typesetting:-merror("unterminated procedure")))
Error, unable to parse
    Typesetting:-mambiguous(  Typesetting:-mambiguous(end,

      Typesetting:-merror("unable to parse")) procsemi)

Ouch! But to confuse things further the following procedures may be entered using 2D math and work fine:
>H := proc (x) x^2*sin(x) end proc;
>K := proc (x) sin(x^2) end proc;
Doesn't make any sense to me. Perhaps 2D math is not ready for prime time?

 

So I have got the following integral:

Int((2*z+1)/(z-5)(z-1)^2,z)

around the square with corners 2, 2i, -2, -2i oriented counter-clockwise.

Do I need to tell Maple that z is complex? Do I need to manually parametrize z? Is Maple aware of Cauchy's theorem?

What is the quickest way of evaluating this sort of integrals.

ode_problem.mw Can someone please look at this? I am having a problem with the ordinary differential equations. 

 

Hello there,

I'm pretty new to MAPLE so this may probably an "easy" mistake, but I don't know what's the problem anyway...

I'd like to find a solution to a system of four equations with four unknowns:

fsolve({(T[1]-T[0])/(10000-T[1]+T[0]) = -2.000000000, (T[2]-T[0])/(20000-T[2]+T[0]) = 0, (T[3]-T[0])/(50000-T[3]+T[0]) = 50, .1*T[0]+.3*T[1]+.55*T[2]+0.5e-1*T[3]-5000 = 0}, {T[0], T[1], T[2], T[3]})

Problem: Instead of providing the single solutions, MAPLE is simply just rewriting the fsolve-statement and does not solve. There is no error-message.

Does anybody know, what the problem is here? Is there no solution after all?

How to let sqrt(5*x+5+y) become sqrt(5*(x+1)+y) automatically?

3 4 5 6 7 8 9 Last Page 5 of 31