{VERSION 5 0 "IBM INTEL NT" "5.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 1 }{CSTYLE "2D Comment" 2 18 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 } {PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "Times" 1 12 0 0 0 1 2 2 2 2 2 2 1 1 1 1 }1 1 0 0 0 0 1 0 1 0 2 2 0 1 }} {SECT 0 {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "restart;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "with(plots):" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 69 " Lets look at the single species discre te population dynamics model" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 10 " " }{XPPEDIT 18 0 "P[t+1]-P[t] = F(P[t ]);" "6#/,&&%\"PG6#,&%\"tG\"\"\"F*F*F*&F&6#F)!\"\"-%\"FG6#&F&6#F)" } {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 5 " or" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 9 " " }{XPPEDIT 18 0 "P[t+1] = f(P[t]);" "6#/&%\"PG6#,&%\"t G\"\"\"F)F)-%\"fG6#&F%6#F(" }{TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 8 " where" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 9 " " }{XPPEDIT 18 0 "f(P[t ]) = P[t]+F(P[t]);" "6#/-%\"fG6#&%\"PG6#%\"tG,&&F(6#F*\"\"\"-%\"FG6#&F (6#F*F." }{TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 6 " for" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 8 " " }{XPPEDIT 18 0 "f(P) = alpha*P-beta*P^2;" " 6#/-%\"fG6#%\"PG,&*&%&alphaG\"\"\"F'F+F+*&%%betaGF+*$F'\"\"#F+!\"\"" } {TEXT -1 1 "." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 15 " Lets define " }{XPPEDIT 18 0 "f(P);" " 6#-%\"fG6#%\"PG" }{TEXT -1 5 " and " }{XPPEDIT 18 0 "F(P);" "6#-%\"FG6 #%\"PG" }{TEXT -1 1 "." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 29 "f := P -> alpha*P - beta*P^2;" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 " y := alpha*P - beta*P^2;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 " " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 17 "F := P -> f(P)-P;" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 5 "F(x);" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 40 " Lets calculate the derivative of f. " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "yp := d iff(y,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "fp := unapply(yp,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 43 " Lets determine where our mod el is valid." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "so lve(f(P)=0,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 57 " \+ Lets find the equilibrium populations for this system." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "solve(y=P,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "solve(f(P)=P,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 69 " Lets determine the two period points and three period points of f." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 19 "solve(f(f(P))=P,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 22 "solve(f (f(f(P)))=P,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 36 " \+ Lets choose an alpha and a beta." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} }{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 13 "alpha := 1+r;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "beta := r/K;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "solve(f(f(P))=P,P) ;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 22 "solve(f(f(f(P)))=P,P); " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "r := 0.3;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "K := 100;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "solv e(f(f(P))=P,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 22 "solve(f( f(f(P)))=P,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 28 " \+ Now lets analyze f and F." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 43 " Lets determine where our model is valid." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "solve(f(P)=0,P);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 45 "plot(\{y,P\},P=0..alpha/beta,color=[blue,red]);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 30 "plot(abs(yp),P=0..alpha/beta);" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "solve(abs(yp)<1,P);" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 27 "plot(F(P),P=0..alpha/beta);" }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 49 " Now lets change our model slightly and \+ consider" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 7 " " }{XPPEDIT 18 0 "P[t+1] = f(P[t])" "6#/&%\"PG6#,&%\"tG\"\" \"F)F)-%\"fG6#&F%6#F(" }{TEXT -1 7 " + g(t)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "g := t -> 10;" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 7 "g(10.);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "P[0] := K/2.;" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "for t from 1 by 1 to 100 do " }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 25 " P[t] := f(P[t-1])+g(t):" }} {PARA 0 "> " 0 "" {MPLTEXT 1 0 4 "end:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "P[100];" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 31 " listplot([seq(P[t],t=0..100)]);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 20 " Now lets consider" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 5 " " }{XPPEDIT 18 0 "P[t+1]-P[t] = f*P[t-1]-d*P[t];" "6#/,&&%\"PG6#,&%\"tG\"\"\"F*F*F*&F &6#F)!\"\",&*&%\"fGF*&F&6#,&F)F*F*F-F*F**&%\"dGF*&F&6#F)F*F-" }{TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 5 " or" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 3 " \+ " }{XPPEDIT 18 0 "P[t+1] = P[t]+f*P[t-1]-d*P[t];" "6#/&%\"PG6#,&%\"t G\"\"\"F)F),(&F%6#F(F)*&%\"fGF)&F%6#,&F(F)F)!\"\"F)F)*&%\"dGF)&F%6#F(F )F2" }{TEXT -1 3 " = " }{XPPEDIT 18 0 "(1-d)*P[t]+f*P[t-1];" "6#,&*&,& \"\"\"F&%\"dG!\"\"F&&%\"PG6#%\"tGF&F&*&%\"fGF&&F*6#,&F,F&F&F(F&F&" } {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 4 " " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 27 " Determine the stability." }}{PARA 0 " " 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 4 " " }{XPPEDIT 18 0 "lambda = (1-d+sqrt((1-d)^2+4*f))/2;" "6#/%'lambdaG*&,(\"\"\"F'%\"dG !\"\"-%%sqrtG6#,&*$,&F'F'F(F)\"\"#F'*&\"\"%F'%\"fGF'F'F'F'F0F)" } {TEXT -1 9 " or " }{XPPEDIT 18 0 "lambda = (1-d-sqrt((1-d)^2+4*f) )/2;" "6#/%'lambdaG*&,(\"\"\"F'%\"dG!\"\"-%%sqrtG6#,&*$,&F'F'F(F)\"\"# F'*&\"\"%F'%\"fGF'F'F)F'F0F)" }{TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 39 "lamb da[1] := (1-d+sqrt((1-d)^2+4*f))/2;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 39 "lambda[2] := (1-d-sqrt((1-d)^2+4*f))/2;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 10 "f := 0.02;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 11 "d := 0.009;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 10 "lambda[1 ];" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 10 "lambda[2];" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "P[0] := K/2.;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "for t from 1 by 1 to 100 do" }} {PARA 0 "> " 0 "" {MPLTEXT 1 0 32 " P[t+1] := (1-d)*P[t]+f*P[t-1]:" } }{PARA 0 "> " 0 "" {MPLTEXT 1 0 4 "end:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 7 "P[100];" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 31 " listplot([seq(P[t],t=0..100)]);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "0 0 0" 8 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 } {PAGENUMBERS 0 1 2 33 1 1 }