0 years, 22 days

## Help much appreciated....

Thank you Acer and Carl for your help. Things look so easy when you know what you're doing.

This is day #14 since I installed Maple.  In frustration, I think I gave up using it about three times so far. You guys on Mapleprimes make a huge difference.

Tom K.

## This syntax works....

This works:

display({plots[odeplot](dsn, [[t, Sx(t), color = green], [t, Ex(t), color = black], [t, Ix(t), color = blue],[t, R(t), color = red]],  0 .. 100, legend = [ Sx(t), Ex(t), Ix(t), R(t)], labels = [t,""] ),PointPlot(FLDat)});

## Can a second plot be combined with a plo...

I appreciate the feedback.  The suggestion does not combined the plots, that is, plot them on the same abcissa, but generates two separate plots. My goal is to compare a model plot to a data plot.

Delayed Differential Equations - SEIR Compartmental Model Modified with 2 Time Delays - Progr

Delayed SEIR Model:

The goal is to model COVID-19 data from Flor

 >
 > restart: with(plots): with(DEtools):with(LinearAlgebra):with(Statistics):with(CurveFitting):with(Statistics): with(Optimization):
 >
 >
 >
 > ddesys := {diff(S(t),t) = -beta*S(t)*Ix(t)/N, diff(Ex(t),t) = beta*S(t)*Ix(t)/N - sigma*Ex(t-tau__1), diff(Ix(t), t) = sigma*Ex(t - tau__1)- gamma*Ix(t-tau__2), diff(R(t),t) = gamma*Ix(t-tau__2), diff(Dx(t),t) = delta*Ix(t), S(0) = 80900, Ex(0) = 1, Ix(0) = 1, R(0) = 0, Dx(0) = 0 };
 (1.1)
 > dsn := dsolve(eval(ddesys, {beta = 4, gamma = 0.0478, sigma = 0.10, delta = 0.0005, N=80900, tau__1 = 1.1,tau__2 = 8.7,tau__3 = 0}), numeric):
 > plots:-odeplot(dsn, [[t, S(t), color = green], [t, Ex(t), color = black], [t, Ix(t), color = blue],[t, R(t), color = red]],  0 .. 64, legend = [ S(t), Ex(t), Ix(t), R(t)], labels = [t,""] ), PointPlot(FLDat);
 (1.2)

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