I have differential equation with x as independent variable that I want to convert to state space representation.

But DynamicSystems will not accept y(x) as the output variable, since it defaults to y(t).

Help under "Description of the Model of a Linear System Object" says it is possible to change the independent variable by changing continuoustimevar setting. But help does not give an example how to do this and all my tries failed.

How to do this? Attached is worksheet showing the problem

Download DS_problem.mw

I have maplesim installed and I get the error "Error, `MapleSim` does not evaluate to a module" when I run A:=MapleSim:-LinkModel(); in a Maple worksheet.

Does anyone know how to solve this error?

how can i get this pde solved ( numeric or analytical)
 

Download pde.mw

Hi guys,

I know how to plot inequality system through using with(plots) and inequal term. however, I couldn't plot following system of inqulity equations:

alpha <= 0.0002500000000*(-18000.*m^2 + 47271.*m + 39514. + sqrt(3.24000000*10^8*m^4 - 1.701756000*10^9*m^3 - 4.266980559*10^9*m^2 - 3.036299412*10^9*m - 6.95987804*10^8))/(9.*m^2 + 12.*m + 4.), 0.00005000000000*(-90000.*m^2 + 237237.*m + 198158. + sqrt(8.100000000*10^9*m^4 - 4.270266000*10^10*m^3 - 1.069976858*10^11*m^2 - 7.612670111*10^10*m - 1.744924704*10^10))/(9.*m^2 + 12.*m + 4.) <= alpha, -0.6666666667 < m, m < -0.6665522013

please let me know how we can plot it.

with best

u(x,t)=sin(x)cos(t) exact solution 

approxmation solution u(x,t) =sin(x)sin(t)

Using t=0 .. 3*Pi the plot is truncated. Changing the 3*Pi to a number, then the full plot shows.

Also keeping 3*Pi but changing y=-1..1 to y=-1.01 .. 1.01 now the full plot shows again.

Is the above normal behaviour or it it a bug?

Download strange_result_of_DEplot.mw

hallo every body 

please can you help me 

how do i solve this differential linear system with respect lambda is positive number  

i use maple 18

Let the differential system with $\lambda>0$

\begin{equation}
\begin{array}{ccc}
\dot{x}=y(t)\\
\dot{y}=z(t)\\
\dot{z}=-\lambda y(t)-h(t)
\end{array}
\end{equation}

prob.pdf

Is there any chance to sort the array in maple and add the non-zero values? PFA the screenshot. I actually intend to add the non-zero values (leaving behind the dumX entries). How can I add the numerical values only?

I installed just today the 15-day trial version of Maple Flow. 

I could get simple 2D plots of functions but did not succeeded in using fieldplot.

Does fieldplot() work in Maple Flow?

.Hello everybody

.In the attached code how I can compute \lambda2(t,s) and Vbar(s) symbolically

 when I run them, some parts can't be computed. how should I solve this problem?

2.mw

Question 1: Given: c^3 = 1000
How can I have MapleFlow 2022 solve for c?

I can do this manually, of course... by entering...
c=1000^1/3 =
But I haven't been able to figgure out how to have MapleFlow solve for "c" automatically.

Question 2: How to find the log to the base 10?
As it  seems the default is base e.

Question 3: What is antilog function for a given base?

Thanks for any help.

Why maple give empty solutions? See ref. (12) in the attached wokrsheet. Is there anything missing when deriving Sols?

sols_tw.mw

hi im currently doing my thesis and can somebody help me to develope the code? pls im stuck..

restart;
_local(I);
Digits := 15;
de1 := (1 - p)*(diff(S(t), t) + mu*S(t)) + p*(diff(S(t), t) + mu*S(t) + beta*S(t)*I(t) - rho*R(t) - varepsilon);
de2 := (1 - p)*(diff(E(t), t) + (alpha1 + mu)*E(t)) + p*(diff(E(t), t) + (alpha1 + mu)*E(t) - beta*S(t)*I(t));
de3 := (1 - p)*(diff(I(t), t) + (alpha2 + delta + mu)*I(t)) + p*(diff(I(t), t) + (alpha2 + delta + mu)*I(t) - alpha1*E(t));
de4 := (1 - p)*(diff(R(t), t) + (mu + rho)*R(t)) + p*(diff(R(t), t) + (mu + rho)*R(t) - alpha2*I(t));
ibvc := S(0) = 2304219, E(0) = 84929, I(0) = 299, R(0) = 71411;
sys1 := eval([de1, de2, de3, de4], p = 1);
dsolve(sys1);
sys0 := eval~(sys1, [{I = 0, R = 0}, {I = 0, S = 0}, {E = 0}, {I = 0}]);
sys_p := `*`~(1 - p, sys0) +~ `*`~(p, sys1);
ode1, ode2, ode3, ode4 := seq(sys_p[j], j = 1 .. 4);
ode1;
de1;
collect(expand(ode1 - de1), S(t), factor);
ode2 - de2;
ode3 - de3;
ode4 - de4;
mu := 0.133*10^(-5);
varepsilon := 0.99879;
delta := 0.004554;
beta := 0.1009*10^(-6);
alpha1 := 0.0008999;
alpha2 := 0.1997;
rho := 0.00090021;
res := dsolve({ibvc, ode1, ode2, ode3, ode4}, numeric, parameters = [p], abserr = 0.1*10^(-14), relerr = 0.1*10^(-12));
res(parameters = [0.5]);
res(50);
plots:-odeplot(res, [t, S(t)], 0 .. 100);
res(parameters = [1]);
plots:-odeplot(res, [t, S(t)], 0 .. 100);
Q := proc(p, {scene::list := [t, S(t)], range::range := 0 .. 100}) if not p::realcons then return 'procname(_passed)'; end if; res(parameters = [p]); plots:-odeplot(res, scene, range, _rest); end proc;
Q(0.5, color = blue);
plots:-animate(Q, [p, range = 0 .. 50], p = 0 .. 1, trace = 24);
n := 4;
s := unapply(add(g[k](t)*p^k, k = 0 .. n), t);
e := unapply(add(h[k](t)*p^k, k = 0 .. n), t);
i := unapply(add(i[k](t)*p^k, k = 0 .. n), t);
r := unapply(add(j[k](t)*p^k, k = 0 .. n), t);
Error, (in i[0]) too many levels of recursion
DE1 := series(eval(ode1, {E = e, I = i, R = r, S = s}), p = 0, n + 1);
DE2 := series(eval(ode2, {E = e, I = i, R = r, S = s}), p = 0, n + 1);
DE3 := series(eval(ode3, {E = e, I = i, R = r, S = s}), p = 0, n + 1);
DE4 := series(eval(ode4, {E = e, I = i, R = r, S = s}), p = 0, n + 1);
Error, (in i[0]) too many levels of recursion
Error, (in i[0]) too many levels of recursion
Error, (in i[0]) too many levels of recursion
Error, (in i[0]) too many levels of recursion
M := eval([ibvc], {E(0) = e(0), I(0) = i(0), R(0) = r(0), S(0) = s(0)});
Error, (in i[0]) too many levels of recursion

I have say  I am taking for example purpose only i need in general

v:="1:1":
k:=4

printf("%s]  is %g, v, k) 

Now i want the %s] part in some other color say green or red some dark color.

the %s is inside which need to replaced by the v which will keep coming

I want it for a general say for some part of the printf in some color

At present atleast i want

let F be a function say F(v,k) and it prints out 

printf("%s]  is %g, v, k)  where it prints out the %s] part in dark color

I want to collect up the equation terms by the numerical value of the terms coefficient? Have tried sort collect combine...
So far the best I have come up with is nops(indets(on each term). And put them in seperate lists. This still doesn't quiet do the trick.
I am looking to achieve. Would to happy to have then as seperate lists or equations.

(a_1^5+a_2^5...)+5(a_1^4a_2+a_1^4a_3....)+10(a_1^3a_2^2 ....)+20(  ....   )+......+60(a_1^2a_2a_3a_4+ a_1a_2^2a_3a_4....)

Download 30-7-22_Q_sort_equation_by_numerical_coeffs.mw