# Non linear differential equation plot [closed]

Consider the following paper:

From my understanding figure 2(on page 5) is a graph of $$s(t), i(t)$$ and $$r(t)$$ by the function in the appendix(page 6) for case 1.

However, when I try plotting this function, I get the wrong out output, why?

Plot[{ 1 -
0.36*t + (0.72*10^-1)*t^2 - (0.96*10^-2)*t^3 + (0.96*10^-3)*
t^4 - (0.768*10^-4)*t^5 + (0.5688888892*10^-6)*t^6,
0.36*t - (0.72*10^-1)*t^2 + (0.96*10^-2)*t^3 - (0.96*10^-3)*
t^4 + (0.768*10^-4)*t^5 - (0.512*10^-5)*t^6}, {t, 0, 10}]


• The solutions in the Appendix are only approximate solutions, not exact; and power-series approximations get worse as their arguments get larger. Note that your graph is pretty good for smaller values of $t$ and only diverges at larger values. Sep 2 at 15:40
• I’m voting to close this question because it arises from confusion about the applicability of certain published results, and has nothing to do with using the Mathematica software correctly or incorrectly. Sep 2 at 15:41
• @MichaelSeifert I meant, my plot isn't plotting what the paper plotted..
– Math
Sep 6 at 11:57
• Presumably the paper is plotting that actual numerical solutions to the differential equations. The Appendix gives power-series approximations to these solutions, not the actual functions (which I suspect can't be written in closed form.) Sep 6 at 13:50
• @MichaelSeifert isn't that defeating the purpose of Adomian decomposition? surely they should be plotting their solutions from Adomian decomposition rather than "actual" numerical solutions? that's what I would've thought anyway.. I have the actual numerical solutions and they match their plots but this is strange since that's not our objective!
– Math
Sep 6 at 14:01