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{SECT 0 {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 "restart;  with(DEtoo
ls): with(plots):" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 66 "Try differen
t values for r and K with the Logistic Growth Equation" }}{PARA 0 "> \+
" 0 "" {MPLTEXT 1 0 144 "DEplot([diff(N(t),t)=subs(\{r=0.5, K=50.0\}, \+
r*N(t)*(1-N(t)/K))],[N(t)],t=0..10, [[N(0)=5.0],[N(0)=65.0]], stepsize
=0.2, title=`Logistic Growth`);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 
90 "Try changing the parameter values (r, c, b, m) for the Lotka Volte
rra Predator Prey Model." }}{PARA 0 "" 0 "" {TEXT -1 76 "Here x(t) = n
umber of prey at time t and y(t)= number of predators at time t" }}
{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 
0 208 "DEplot(subs(\{r=1, c=1, b=0.3, m=0.3\},[diff(x(t),t)=r*x(t)-c*x
(t)*y(t),\ndiff(y(t),t)=b*y(t)*x(t)-m*y(t)]),\n[x(t),y(t)],t=0..20,[[x
(0)=1.2,y(0)=1.2],[x(0)=1,y(0)=.7]],stepsize=.2,\ntitle=`Lotka-Volterr
a model`);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 39 "SIR Model - change \+
the parameter values" }}{PARA 0 "" 0 "" {TEXT -1 96 "r = birth rate, d
 = death rate, a = infection rate, b = recovery rate, N = total popula
tion size" }}{PARA 0 "" 0 "" {TEXT -1 78 "x(t) = number of susceptible
s at time t, y(t) = number of infectives at time t" }}{PARA 0 "" 0 "" 
{TEXT -1 47 "Note: you need to change a and d in two places." }}}
{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 289 "DEplot(subs(\{r=0.4, N=100.
0, a=0.1, d=0.4, b=0.4\},\n[diff(x(t),t)= r*N-a*x(t)*y(t)-d*x(t),\ndif
f(y(t),t)=a*x(t)*y(t)-b*y(t)-d*y(t)]),\n[x(t),y(t)],t=0..100,[[x(0)=99
,y(0)=1],[x(0)=15, y(0)=5]],stepsize=.2,\ntitle=`Spread of Disease`,li
necolor=[green, blue],\nlabels=[`Susceptible`,`Infected`]);" }}}}
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