{VERSION 6 0 "IBM INTEL NT" "6.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 1 }{CSTYLE "" -1 256 "" 1 14 0 0 0 0 0 1 0 0 0 0 0 0 0 0 } {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 }{PSTYLE "Maple Output" -1 256 1 {CSTYLE "" -1 -1 "Times" 1 14 0 0 0 1 2 1 2 2 2 2 1 1 1 1 }3 3 0 0 0 0 1 0 1 0 2 2 0 1 }{PSTYLE "" 0 257 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 }3 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 257 "" 0 "" {TEXT 256 21 "Predator Prey System\n " }{TEXT -1 39 "Example 1, page 545: Rabbits and Wolves" }{MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 23 "restart; with(DEto ols):" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 98 "SYS:= [ D(R)(t) = 0.08*R( t) - 0.001*R(t)*W(t),\n D(W)(t) = -0.02*W(t) + 0.00002*R(t)*W(t )];" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 54 "dfieldplot(SYS,[R(t) ,W(t)],t=0..1,R=0..2000,W=0..150);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 74 "ODE := D(W)(R) = (-0.02*W(R) + 0.00002*R*W(R))/(0.08* R - 0.001*R*W(R)); " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "si mplify(%);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 17 "dsolve(ODE,W( R));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 38 "dsolve(\{ODE,W(500) =25\}); WW := rhs(%);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 41 "pl ot(WW,R=0..5000,view=[0..5000,0..200]);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 156 "phaseportrait(SYS,[R(t),W(t)],t=0..250,[[W(0)=25,R(0 )=500],\n[W(0)=100,R(0) = 1200]],linecolor=[blue,black],thickness=2,st epsize=0.1,\nview=[0..5000,0..200]);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 137 "SYS1:= [ D(R)(t) = 0.08*R(t) - 0.001*R(t)*W(t),\n \+ D(W)(t) = -0.02*W(t) + 0.00002*R(t)*W(t),\n R(0)=500, W( 0) = 25 ];" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 46 "sln := dsolve( SYS1,[R(t),W(t)],type=numeric);\n" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 61 "with(plots):\nodeplot(sln,[[t,R(t)/1000],[t,W(t)/80]] ,0..400);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "12 " 0 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }