{VERSION 3 0 "IBM INTEL NT" "3.0" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 }{PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "Text Output " -1 2 1 {CSTYLE "" -1 -1 "Courier" 1 10 0 0 255 1 0 0 0 0 0 1 3 0 3 } 1 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "Warning" 2 7 1 {CSTYLE "" -1 -1 "" 0 1 0 0 255 1 0 0 0 0 0 0 1 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "Maple Output" 0 11 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }3 3 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }{PSTYLE "" 0 256 1 {CSTYLE "" -1 -1 "" 0 1 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 }{PSTYLE "" 0 257 1 {CSTYLE "" -1 -1 "" 0 1 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 }{PSTYLE "" 0 258 1 {CSTYLE "" -1 -1 "" 0 1 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 }{PSTYLE "" 0 259 1 {CSTYLE "" -1 -1 "" 0 1 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 0 "" 0 "" {TEXT -1 33 "Local Stability worked exa mple 2." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 43 "Find the equilibria of the nonlinear syst em" }}{PARA 256 "" 0 "" {OLE 1 4108 1 "[xm]Br=WfoRrB:::wk;nyyI;G:;:j:: >:B>N:F:nyyyyy]::yyyyyy::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::fyyyyya:nYf::G:jy;:::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::JcvGYMt>^:fBWMtNHm= ;:::::::n:;JZC:bKB::>r>^g]Hh:oq;V:>Z?B:<:=ja^GE=;::::::: ::N;?R:yyyyyyA:yayA:<::::::JDJ:j::F@[KaFFcmnnHEM:>:::::::oJ;Zy=J:B:::: ::F:;JBC:j:VBYmp>HYLkNG>::::::::N;N;;Jyk?J@>:UJ:n;v;;JBCR:HjkmZ:BZATRWuREEUv:IJ:>:::::F:wyyAb:;P:<:TNC>:UT RcETcTX[US;SK]UW=EWMuUWm>j\\@A:::cYH_WV;J:<::::::::yayY:^Z:j:>:yayQ:>: NkFJcM:?s:F:MZ=FL;J;f<>:E:Mb:B:CZ:NZ;F:E:=b:yyyyI:E:M:;;JZyy^yYJhjNLj?JMJ@fc[;PP:>VEZ:F;NZ :vCS=[LsfFaMR>@>Z::::::::kJ;@:;J;>Z:vYxY:>Z::::::j @>Z::::::::kJ:vYxI:;Z::::::JywYB:::::::::::::yay=J:B:::::::::::::::::: :jysy:>:<::::::::FjxM:<:[V:;B:DZ<>ZJfcN?^??inOh[cFC:US:F[:>Z:N`DV c;>H=B:IOO?>Z:N@Vb>N:>isOOOo>J SVs=>E=:mMO;_;og:=J:FI:_;yH;=J:>i:J?JSJ=XJ;>:kUXj>JSjjaj:>:m=[Z:VYZ:JB AJ:b:DZJVdscRYEUPK<<:UK:^:>X=j>>:_c:U;JSJfQj:jOVTJSJN]j:>:U;e:qAB:>l;Z:b:^dcSS::kJ<<:US:=J< Jr?:MJ:N@illHj::C:[q:F;;JSdjIHJMej::[Z:VY[j=B:;JXE:X:;:::::::::::::::::::::::::::::::::::::::::::::::::1:" } {TEXT -1 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 30 "and determine the ir stability." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 34 "First find the equilibrium points." }}}{EXCHG {PARA 0 "> \+ " 0 "" {MPLTEXT 1 0 8 "restart:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "with(linalg):" }}{PARA 7 "" 1 "" {TEXT -1 32 "Warning, new def inition for norm" }}{PARA 7 "" 1 "" {TEXT -1 33 "Warning, new definiti on for trace" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "with(DEtool s):" }}{PARA 7 "" 1 "" {TEXT -1 35 "Warning, new definition for adjoin t" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 10 "f:=-2*x*y;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "g:=y-x+x*y-y^3;" }{TEXT -1 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 23 "solve(\{f=0,g=0\},\{x,y\}); " }}{PARA 11 "" 1 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 48 "The equilibrium points are (0,0), (0,1), (0,-1)." }}{PARA 0 "" 0 " " {TEXT -1 78 "Note that the final bracket only gives the point (0,0) \+ which is already given." }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 27 "To fin d the Jacobian matrix" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 10 "f: =-2*x*y;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "g:=y-x+x*y-y^3; " }{TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "v:=[f,g]; " }{TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 21 "J:=jacob ian(v,[x,y]);" }}{PARA 11 "" 1 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 18 "At the point (0,0)" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 29 "J0:=subs(\{x=0,y=0\},evalm(J));" }}{PARA 11 "" 1 "" {TEXT -1 0 "" }}}{EXCHG {PARA 257 "" 0 "" {OLE 1 4104 1 "[xm]Br=WfoRrB :::wk;nyyI;G:;:j::>:B>N:F:nyyyyy]::yyyyyy::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::fyyyyya:nYf::G:jy;:::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::J cvGYMt>^:fBWMtNHm=;:::::::n:;JZC:bKB::>r>^g]Hh:oq;V:J:B: F:YLpfF>:::::::::J?NZ;vyyyyyY:vYxY:B:::::::c:;:=:jR>@Wlj^HMMufF;J::::: ::N=?:xI:;Z::::::j:>:C>;:=j[vGUMrvC?MoJ::::::::JCN:yyyxI:;Z::::::j;B:s <;:wA?Z:F;^:nYn:v:J?>:wAQ:SJ:f;;JAjA>:[B::wAyA::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::=ZAFW_rZ_u:=J:@JCHR_DJ>=]Z:R:[DZATRWuREEUv:IJ:>:::::FZ:nyyYZDjysyQj;J:>R;B:bK_J: fc[_hb_ds?h_?^?GhoGfnGgioGM:ETV:::^xsNpk?:;B::::::::vYxy;J<<:=J:vYxY;J :jj;B:?B:e:;j<;>ryAryAfGb:Q:G;Sj`@@J:>f:f:;B:M :?B:YLpJbNHEms>@[;;B:::::::JFNZ;J:N:;B:yayA:;B::::::f:=;jysy:>:<::::::wqy[:::::::::::::vYxI:;Z::::::::::::::::: :::yay=J:B::::::::jDB:qi:;fyB:>l;F:>ZcTTUUSaEBWTSiEB_tUUURWML^:f_;J ?B:_c<;V:cK;>:;:::::::::::ceVQmDG;;B:_;WY:=Z:NCOO@>Z:N@Fk@V:^f__H;POWG M:_;wR<=:Ol;>:::jL^:f?=JZ:>@;p>JSjkPj:jR @B:N@VoFF:>@><:C:[q:F;;J SFm;fb;F:;B:?MyF;N@oV:qu:=J:vFw=N@mnt\\j:Jk:N@onOej:jmJBB:qQ:[:JBA:DZ< B>aTXDpql`R^:f?=JJUD;=J:l;Z:b:^DP@: JL:UK:^:>X=j>>:_;Eb;=J:f:N;n>N;yyyxy:J:>< " 0 "" {MPLTEXT 1 0 23 "A:=diff(x(t),t)=-2* x*y;" }}{PARA 11 "" 1 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 28 "B:=diff(y(t),t)=y-x+x*y-y^3;" }}{PARA 11 "" 1 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 118 "DEplot(\{A,B\},\{x(t),y(t)\},-50..50,[[0,1 ,1],[0,-.1,.1],[0,0.1,-0.1],[0,-0.1,-0.1]],x=-0.5..0.5,y=-0.5..0.5,ste psize=.1);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 86 "The phase portrait \+ suggests the equilibrium point of the nonlinear system is unstable." } }{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 18 " At the point (0,1)" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 29 "J1:=s ubs(\{x=0,y=1\},evalm(J));" }}{PARA 11 "" 1 "" {TEXT -1 0 "" }}} {EXCHG {PARA 258 "" 0 "" {TEXT -1 1 " " }{OLE 1 4616 1 "[xm]Br=WfoRrB: ::wk;nyyI;G:;:j::>:B>N:F:nyyyyy]::yyyyyy:::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::fyyyyya:nYf::G:I:wAyA:::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :NDYmq^H;C:ELq^H_mvJ::::::::gjR<:T><::;H;Sub]EJwW:A:;f ;B:F:YLpfF>:::::::::J?NZ;vyyyyyY:vYxY:B:::::::c:;:=:jR>@Wlj^HMMufF;J:: :::::N=?:xI:;Z::::::j:>:CA;:=j[vGUMrvC?MoJ::::::::JCN:yyyxI:;Z::::::j; 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Mq;@::::TrPDJ>M=[DZATRWuREEUv:IJ:>:::::FZ:nyyYZDjysyQj;J:>R;B:bK_J:fc[ _hb_ds?h_?^?GhoGfnGgioGM:ETV:::^xsNpk?:;B::::::::vYxy;J<;jwDZ:N\\=j:F;Hj>A:?jDJ:f:;j>D:;B:C:?R:=jZ:^:n_;>=E:] c:=Z:f:V[b<>vHn;n^@v;_jysy;B:K:;xy;xy;g=Dj?JMJ@fc[;>:;m@[;;B:::::::JFNZ;J:Z:vYxY:>Z::::::jD_=a= [;;B:::::::JF>:yay=J:B::::::nYyA<::::::::::::jysy:>:<::::::::::::::::: ::vYxI:;Z:::::::::eZ:Vy<>jx]:JBAj:J:DZJ^dcgg_WhZnc_whZNdigg[oGSLj;^@?J:>:::::::::::^hlWGen>>Z:N@nw;F:r:NO Qm>JSJg`j:J_jDjw;<:[V:;B:::jf^:f?=JRM:dZ;v j?F:>@;@N@^_DF:B:;@b<@Jaqj:JT>R[Z:VY;RyB:>l;Z:b::C:[ q:F;;JSFm;fb;F:;B:?MyF;N@oV:Iv:=:IMy:_kFGpBF:NF:_KGWxDFZ:jmJBB:qQ:[:JB A:DZ<>ZJVdscRYEUlKF:;B:ukcG;N@frEF:fA:_;qI==:UC:a pDjw;<:[V:B:D:c\\_;:^[j`:f_;>:C:[q:F;;JSjZTj:>Z:^?;E:O:G;OjyyiyI:>:[Z: VY[j=J:^qX;j;:::::::::::::::::::::::: ::::::::::::::::::::::::::::::::5:" }{TEXT -1 0 "" }}}{EXCHG {PARA 0 " " 0 "" {TEXT -1 164 "The equilibrium point of the linearisation is a s addle and by the linearisation theorem the point (0,-1) of the nonline ar system is unstable and a nonlinear saddle." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 136 "Plot the phase diagram o f the system and check that the equilibrium points show the geometric \+ features determined by analytical methods." }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 190 "DEplot(\{A,B\},\{x(t),y(t)\},-10..50,[[0,.1,0.5],[ 0,-.1,1.9],[0,0.1,1.9],[0,0.1,.5],[0,-.01,-.5],[0,.01,-.5],[0,-.1,-1.1 ],[0,0.1,-1.1],[0,.02,0.1],[0,.02,-0.1]],x=-0.1..0.1,y=-2..2,stepsize= .1);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "30 0 1 " 0 }{VIEWOPTS 1 1 0 1 1 1803 }