Maple 2018 Questions and Posts

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

I want to solve system of nonlinear ordinary differential equations numerically using the variational finite
element method (FEM). is it possible to solve on Maple? If anybody have a idea please share with me. I attach the image of my problem which I am tryimng to solve.

How do i change keyboard shortcuts, E.g one of my keyboard keys are broken or have stopped working. How do i redirect my shortcut to another keyboard combination or another hotkey simply.

Hello, is it possible to have a document synchronized in the same way as Onenote? We're a group of engieneer students wanting to share documents, however the only way we can figure out a way to do it. Is uploading to maplecloud groups, sharing a "base" document, and everytime someone "updates" the document you save a new one. So it kind of defeats the purpose of making it a smart idea of collaborating on one document, am i missing something or is this really how oldschool it works?

I was wondering how Maple cope with piecewise functions during forward integration and if it's preferable to use dsolve events option in place of defining a piecewise discontinuos function.

As far as I understood dsolve/events halts the integration each time an event is triggered and subsequently restarts the integration using the pre-trigger outputs as new initial conditions. I suppose that by using a piecewise, if a discontinuity is detected, dsolve proceeds exactly in the same way halting and restarting the integration.

Here a toy example of a 2D rolling dice (idea of a rolling dice from the rolling cube by @one man :P ) in which the reaction forces of the floor can be seen as function of the compenetration dice/ground

Both the appraches (events and piecewise) give the same results

falling_dice.mw

How I can solve these time delay  differential equations?

please see attatched files.

Best

Doc191.pdf

ny.mw

 


 

restart; d[1] := 1; d[2] := 4; d[3] := 1; r[1] := 1; r[2] := 1; r[3] := 1; r[4] := .5; a[11] := .5; a[12] := 3; a[21] := 2; a[22] := .8; a[23] := 1; a[32] := .5; a[33] := .9; tau := .3

diff(u(t, x), t) = d[1]*(diff(u(t, x), x, x))+u(t, x)*{r[1]-a[11]*u(t, x)-a[12]*v(t, x)}

diff(u(t, x), t) = diff(diff(u(t, x), x), x)+u(t, x)*{1-.5*u(t, x)-3*v(t, x)}

(1)

diff(v(t, x), t) = d[2]*(diff(v(t, x), x, x))+v(t, x)*{r[2]+a[21]*u(t-tau, x)-a[22]*v(t, x)-a[23]*w(t-tau, x)}

diff(v(t, x), t) = 4*(diff(diff(v(t, x), x), x))+v(t, x)*{1+2*u(t-.3, x)-.8*v(t, x)-w(t-.3, x)}

(2)

diff(w(t, x), t) = d[3]*(diff(w(t, x), x, x))+w(t, x)*{r[3]+a[32]*v(t, x)-a[33]*w(t, x)}

diff(w(t, x), t) = diff(diff(w(t, x), x), x)+w(t, x)*{1+.5*v(t, x)-.9*w(t, x)}

(3)

0 < x and x < Pi, t > 0

0 < x and x < Pi, 0 < t

(4)

diff(u(t, x), x) = 0, diff(v(t, x), x) = 0, diff(w(t, x), x) = 0, x = 0, x = Pi, t >= 0

diff(u(t, x), x) = 0, diff(v(t, x), x) = 0, diff(w(t, x), x) = 0, x = 0, x = Pi, 0 <= t

(5)

u(t, x) > 0, v(t, x) > 0, w(t, x) > 0, `in`(t, x, `&x`([-tau, 0], [0, Pi]))

0 < u(t, x), 0 < v(t, x), 0 < w(t, x), `in`(t, x, [-.3, 0]*[0, Pi])

(6)

``

``


 

Download ny.mw

Hello people in mapleprimes,

I installed maple 2018 Japanese version.
And, with solve(x^2-1,x), its solution is expressed as _EXPSEQ(1, -1)

I know this expression is an internal represantation.
How can I have maple answer as 1, -1?

Thanks in advance.

Addition: my pc is mac osx 10.13.6.
 

 

 

Hi , 

I want to ask if there is any maple code of how to construct wavelet to solve fractional differential eqautions? Or any reference may be help me 

thanks 

Hi,

I'm trying to solve this system of differential equation, coming from the iterative process of the Elastic Curve's  solution.

The problem is that Maple returns:

risultato12 := NULL

EDIT: i think the problem is related to the non-linear equations in the system.

Any suggestion?

Here is the file

https://1drv.ms/u/s!AuhHGe410qgOm1_PdEDqkO4J1YYp

Hi all

Hope the best for all. 

I have a single product of two sum, where the second sum admits one variable, namely j, from first one.

how can I it via maple?

thanks for any help.

HELLO

I AM A STUDENT AND WAS LOOKING FOR USING MAPLE2018.

I REQUESTED FOR A MAPLE EVALUATION. MY QUESTIONS ARE:

FOR HOW LONG CAN I USE THIS EVALUATION VERSION?

SECONDLY, WHAT SOFTWARE FACILITIES I WOULD NOT GET WITH THIS EVALUATION VERSION? WHAT ARE THE DIFFERENCES BETWEEN THE PRICED ENTERPRISE VERSION AND MAPLESOFT EVALUATION VERSION?

THIRDLY, WHAT ARE THE DIFFERENCES BETWEEN MAPLESOFT STUDENT VERSION AND THE ULTIMATE PRICED ENTERPRISED VERSION?

PLEASE REVERT BACK TO ME AT THE EARLIEST.

Hello guys

I have a simple but crucial question about variation, especially in cosmology and gravity. suppose we have the action such as

S=int(sqrt(-g)*F(R,RµναβRµναβ),d^4x) where g is determinant metric gµν and d^4x is space in 4D and F is an arbitrary function of R (Ricci scalar) and scalar which created by Riemann tensor. How we can define this action in the maple 18 and take variation with respect to the metric.

thanks

Essentially I have this trigonometric equation and I want to solve (get the roots of) it within the range -Pi..Pi:

v := a+b*cos(t)-c*(d*(1-(a+b*cos(t))^2-d^2*sin(t)^2)^(1/2)+e*sin(t)) = 0;
v1 := t > -Pi;
v2 := t < Pi;

Where t is the variable and a..e are constants.  At the moment I am trying the following:                  
solve({v, v1,v2}, t, allsolutions, explicit);


My problem is that Maple tries to solve this - I get Evaluating in the bottom left corner of the window - but never seems to return with a solution even after using 52,000s and 5GB of memory: I am using a late model macbook.

Can anyone see a way of re-framing this equation so that Maple can return an answer?

I have a say sum(F(k) ,k=1..n)  It fails unless n is an actual integer.  But sum(F(k), k=1..a) works. Then then eval(%,a=n) completes it. That is probably correct but not necessarily a valid assumption. Details in attached. Also it is hard to understand the error message.
 

restart

``

``

Sinta := (k^2+n^2-k)*n/((k^2+n^2-2*k+1)*(k^2+n^2))

(k^2+n^2-k)*n/((k^2+n^2-2*k+1)*(k^2+n^2))

(1)

Ai := sum(Sinta, k = 1 .. n)

-((1/2)*I)*(2*n^2+I*n)*Psi(n-I*n)/(4*n^2+1)+((1/2)*I)*(2*n^2-I*n)*Psi(n+I*n)/(4*n^2+1)+((1/2)*I)*(-2*n^2+I*n)*Psi(n+1-I*n)/(4*n^2+1)-((1/2)*I)*(-2*n^2-I*n)*Psi(n+1+I*n)/(4*n^2+1)+((1/2)*I)*(2*n^2+I*n)*Psi(-I*n)/(4*n^2+1)-((1/2)*I)*(2*n^2-I*n)*Psi(I*n)/(4*n^2+1)-((1/2)*I)*(-2*n^2+I*n)*Psi(1-I*n)/(4*n^2+1)+((1/2)*I)*(-2*n^2-I*n)*Psi(1+I*n)/(4*n^2+1)

(2)

Souta := n/(k^2+n^2-k)

n/(k^2+n^2-k)

(3)

NULL

sum(Souta, k = 1 .. n)

Error, (in assuming) when calling 'Dfnt_4'. Received: 'when calling 'Dfnt_4'. Received: 'when calling 'unknown'. Received: 'invalid input: Dfnt_4 expects its 3rd argument, fpts, to be of type Or(list, piecewise), but received 0'''

 

"(->)"

Error, invalid input: evalf[10] expects 1 argument, but received 0

 

 

 

This works

sum(Souta, k = 1 .. a)

n*Psi(a+1/2-(1/2)*(-4*n^2+1)^(1/2))/(-4*n^2+1)^(1/2)-n*Psi(a+1/2+(1/2)*(-4*n^2+1)^(1/2))/(-4*n^2+1)^(1/2)-n*Psi(1/2-(1/2)*(-4*n^2+1)^(1/2))/(-4*n^2+1)^(1/2)+n*Psi(1/2+(1/2)*(-4*n^2+1)^(1/2))/(-4*n^2+1)^(1/2)

(4)

Ao := eval(%, a = n)

n*Psi(n+1/2-(1/2)*(-4*n^2+1)^(1/2))/(-4*n^2+1)^(1/2)-n*Psi(n+1/2+(1/2)*(-4*n^2+1)^(1/2))/(-4*n^2+1)^(1/2)-n*Psi(1/2-(1/2)*(-4*n^2+1)^(1/2))/(-4*n^2+1)^(1/2)+n*Psi(1/2+(1/2)*(-4*n^2+1)^(1/2))/(-4*n^2+1)^(1/2)

(5)

"(->)"

n*Psi(n+.5000000000-.5000000000*(-4.*n^2+1.)^(1/2))/(-4.*n^2+1.)^(1/2)-1.*n*Psi(n+.5000000000+.5000000000*(-4.*n^2+1.)^(1/2))/(-4.*n^2+1.)^(1/2)-1.*n*Psi(.5000000000-.5000000000*(-4.*n^2+1.)^(1/2))/(-4.*n^2+1.)^(1/2)+n*Psi(.5000000000+.5000000000*(-4.*n^2+1.)^(1/2))/(-4.*n^2+1.)^(1/2)

(6)

````

``


 

Download Summation_problem.mw

From  time to tiime Malel emits a sort of "Boiing" noise when I make a keyboard error. I am not sure exaclty when it does this, but it is loud. Is it possible to turn it off? I have looked quite extensively and cannot find out anything.

is possible to solve these partial differential equations in maple via pdsolve?

Thanks

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