## why DEplot behave differently when using different...

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?

 > interface(version);

 > restart; ode := diff(y(t), t$2) + y(t)=0; DEtools:-DEplot(ode, y(t), t=0 .. 3*Pi, y=-1 .. 1,[[y(0)=1,D(y)(0)=0]],linecolor=blue);  > #replacing 3*Pi by a number, then it shows the full plot restart; ode := diff(y(t), t$2) + y(t)=0; DEtools:-DEplot(ode, y(t), t=0 .. 10, y=-1 .. 1,[[y(0)=1,D(y)(0)=0]],linecolor=blue);

 > #keeping 3*Pi but changing the y range, it now also show the full plot restart; ode := diff(y(t), t$2) + y(t)=0; DEtools:-DEplot(ode, y(t), t=0 .. 3*Pi, y=-1.01 .. 1.01,[[y(0)=1,D(y)(0)=0]],linecolor=blue);  > Download strange_result_of_DEplot.mw ## differential system... Asked by: hallo every body please can you help me how do i solve this differential linear system with respect lambda is positive number i use maple 18 Let the differential system with$\lambda>0\$

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


prob.pdf

## Is there any chance to sort the array in maple and...

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?

## Is it possible to make 2D vector field plots in Ma...

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?

## how can I compute these integrals symbolically?...

.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

## MapleFlow solve: c^3=1000 ?...

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?...

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

sols_tw.mw

## How do i solve a system nonlinear diferential equa...

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

## text in color in places in printf...

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

## How can an equation be sorted by numerical value o...

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....)

## Why maple return trivial solution after integratio...

Why maple return trivial solution after integration (see (11) in the attached .mw))? The result should be some non-trivial solution.

solutionsg.mw

## Why can't Maple solve the below code for some par...

Hello everybody.

I wrote the attached code. this code gives a good result when "H" parameter is equal to 0.5. Even in this condition if I change other parameters, I can get a true result as well. But when I change "H" parameter to 0.6,0.7,0.8 or 0.9 the code can't be executed anymore and I can't get a result.

based on the paper, for H=0.6,0.7,0.8 or 0.9. we have a result.

what's the problem?

1.mw

## plot three dimensional curve using data points...

Dear all

I need your help to plot

1)   First:  a three dimensionl curve, that is plot F(X,Y), where X, Y, and F(X,y) is given

curve_three_d.mw

2) Second: can plot all the curves in the same graph ( 2-dimensional curve)  obtained from the following idea
for j from 0 by 5 to 40
plot( F(X,j), X)
end for

## Drawgraph of very large size neatly...

Need help to use DrawGraph to align vertices and edges and length etc for very large large size graph which i want to analyze

even if the graph even if it requires to writen to a file to make it more big and neatly visible.

kind kind help please it will be acknowledged

Program attached those cartesian product graphs are huge extra parameters and layouts and may others may be required to make such big big graphs visible. Kind help please.