{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 Input" 2 19 "" 0 1 255 0 0 1 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 22 "m:=1;a:=3;b:=0.5;c:=1:" }}{PARA 0 "
> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 
12 "x0:=3;v0:=2;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 "fs:=\{x
(t),v(t)\}:ini:=x(0)=x0,v(0)=v0;" }}}{EXCHG {PARA 0 "> " 0 "" 
{XPPEDIT 19 1 "de:=diff(x(t),t)=v(t),diff(v(t),t)=-a/m*x(t)-b/m*signum
(v(t));" "6#>%#deG6$/-%%diffG6$-%\"xG6#%\"tGF--%\"vG6#F-/-F(6$-F/6#F-F
-,&*(%\"aG\"\"\"%\"mG!\"\"-F+6#F-F9F;*(%\"bGF9F:F;-%'signumG6#-F/6#F-F
9F;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 38 "sol:=dsolve([de,ini]
,fs,type=numeric);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 17 "op(2,
sol(10)[3]);" }}{PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 
"> " 0 "" {MPLTEXT 1 0 12 "with(plots);" }}}{EXCHG {PARA 0 "> " 0 "" 
{MPLTEXT 1 0 33 "pl1:=odeplot(sol,[t,x(t)],0..18):" }}}{EXCHG {PARA 0 
"> " 0 "" {MPLTEXT 1 0 31 "t:=0:tm:=18:h:=0.0005;npt:=100:" }}{PARA 0 
"> " 0 "" {MPLTEXT 1 0 36 "imx:=floor(tm/h);np:=floor(imx/npt);" }}
{PARA 0 "> " 0 "" {MPLTEXT 1 0 256 "vi:=v0:xi:=x0:j:=0:\nfor i from 1 \+
to imx do\nf1:=vi:\nf2:=-a/m*xi-b/m*signum(vi):\nif(vi*(vi+h*f2)>0 or \+
a*abs(xi)>c) then \nxi:=xi+h*f1:\nvi:=vi+h*f2:\nend if:\nt:=t+h:\nif (
(i mod np)=0) then\nj:=j+1:px[j]:=xi:pv[j]:=vi:pt[j]:=t:\nrk[j]:=op(2,
sol(t)[3])\nend if:\nod: " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 
48 "plot(\{[pt[s],px[s]-rk[s]] $s=1..j\},style=point);" }}}{EXCHG 
{PARA 0 "> " 0 "" {MPLTEXT 1 0 47 "pl2:=plot(\{[pt[s],px[s]] $s=1..j\}
,style=point):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "display([
pl1,pl2]);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "1
4" 0 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }