## 355 Reputation

11 years, 285 days

## `=` expects 2 arguments but received 3...

@Preben Alsholm When I apply to a more complicated one then I get an error

Eq1:=(diff(P1(X, Y), Y, Y))*exp(2*epsilon*alpha[2]-epsilon*alpha[3])+(diff(T(X, Y), X))*exp(epsilon*alpha[1]-epsilon*alpha[4])-(diff(P(X, Y), X))*exp(epsilon*alpha[1]-epsilon*alpha[5]);

indets(Eq1,specfunc(anything,exp));
ln~(%) assuming real;
`=`(op(%));
simplify(%/epsilon);

Error, invalid input: `=` expects 2 arguments, but received 3

## Exactly!...

@Preben Alsholm You have read my mind. Thanks.

How to equate the terms in the exponents from the output?

pp:=combine(dchange({Xsubs2,Ysubs2,psubs2},Eq,[X,Y,P]));

to get

2*alpha[2]-alpha[3] = 2*alpha[1]-alpha[3]

Cheers!

## the output...

I think, the issue is with replacing infinity with 10000.

## Exactly!...

@Preben Alsholm Your are right, I'm looking for a stable limit cylce and now need to follow whatever you have suggested.

Cheers!

## output...

with ,obsrange=false the output look more complicated.

DEplot([Eq1,Eq2,Eq3,Eq4,Eq5],[x(t),y(t),z(t),v(t),w(t)],t=0..70,x=5..7.2,y=0.2..1.6,initialset,stepsize=0.1,color=blue,linecolor=magenta,

arrows=medium,axes=boxed,scene= [x(t),y(t)],obsrange=false)

## something like this...

The desired one if possible, should look like this,

## empty plot...

@Carl Love Thanks

I'm getting empty plot when I do this

A:=DEplot([Eq1,Eq2,Eq3,Eq4,Eq5],[x(t),y(t),z(t),v(t),w(t)],t=0..140,x=5.2..7.2,y=0.2..1.6,initialset,stepsize=0.01,

color=blue,linecolor=magenta,arrows=medium,axes=boxed,scene= [x(t),y(t)]);

Here is the PDF.

delay.pdf

CHeers!

## workaround...

Sorry for the confusion.

How does the procedure (when using procedural input) have to look for a delay differential equation if it is at all available to the user?

ricket-365.tv/free-cricket-streaming.html

## Method of Steps...

I'm wondering maybe Maple can still handle DDEs with a Proc.

## Possible way out?...

Probably, the bugged results matches with the published one.

With my Maple 18, I get the error.

The delays are constant and positive. In this case, tau1 and tau2 (delays) are assumed to be 10.

The history is constant for this problem

x(t)=1, y(t)=1, v(t)=5, and z(t)=1. t<=0.

Update

I tried your example with Maple 18 but get the same error.

## Error...

@Preben Alsholm

But i get this

restart:

Eq1 := diff(x(t), t) = 1-.1*x(t)-0.5e-3*x(t)*v(t)/(1+0.1e-5*v(t));

Eq2 := diff(y(t), t) = 0.5e-3*x(t-10)*v(t-10)/(1+0.1e-5*v(t-10))-.3*y(t)-y(t)*z(t);

Eq3 := diff(v(t), t) = 200*y(t-10)-8*v(t);

Eq4 := diff(z(t), t) = 2*y(t)*z(t)-.15*z(t);

ics := x(0) = 1, y(0) = 1, v(0) = 5, z(0) = 1;

res:=dsolve({Eq1,Eq2,Eq3,Eq4,ics},numeric);
plots:-odeplot(res,[t,x(t)],0..100);

Error, (in dsolve/numeric/process_input) input system must be an ODE system, got independent variables {t, t-10}

Any comment?

## Apparently...

@Kitonum  FIrst of all, thanks for your interest.

I think, you are just trying to replicate the Figure?

## Thanks...

@Markiyan Hirnyk Thanks dear for a very nice and helpfull explanation. If there is something else, I have nowhere else to go?

I still don't understand, why the authors need to present inaccurate plot (Fig 2.).

Cheers!

## Just one clarification...

How you manange to consider 0 < t and t < theta[m], 1/2-(1/2)*phi+t*phi/theta[m], 1)  from the assumptions.?

0<t part is clear but  not t < theta[m].

Cheers!

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