{VERSION 2 3 "SUN SPARC SOLARIS" "2.3" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 }{CSTYLE "2D Output" 2 20 "" 0 1 0 0 255 1 0 0 0 0 0 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 0 }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 }} {SECT 0 {EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 77 " Some code to find eigenvalue equations for 2nd order different ial operators:" }}{PARA 0 "" 0 "" {TEXT -1 69 " Specify the operator L and the boundary operators BC1 and BC2 below." }}{PARA 0 "" 0 "" {TEXT -1 2 " " }}{PARA 0 "" 0 "" {TEXT -1 73 "Warning: Maple doesn't \+ always put things in the correct \"form\" when using" }}{PARA 0 "" 0 " " {TEXT -1 61 " the assume command in conjunction with d solve." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 36 " Define the 2 nd order operator here:" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "L:=U->diff(U,x$2):" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 82 " Defi ne the boundary conditions here using general linear boundary operator BC" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 49 "BC:=(U,a,b,X0)->eval(subs(x=X0,a*U+b*diff(U,x))):" }} }{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 11 "a:=-1:b:=1:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "BC1:=U->BC(U,1,0,a):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "BC2:=U->BC(U,1,0,b):" }}}{EXCHG {PARA 11 "" 1 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 79 " The ge neral solution of the differential equation will depend on the value o f" }}{PARA 0 "" 0 "" {TEXT -1 72 " lambda. Here we generate all solu tions for lambda <0, =0, >0 and then" }}{PARA 0 "" 0 "" {TEXT -1 33 " \+ consider eigenvalue equations " }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 "lambda:='lambda':assume(lamb da<-1/4);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 44 "UM:=rhs(dsolve (L(u(x))=lambda*u(x),\{u(x)\}));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>% #UMG,&*&%$_C1G\"\"\"-%$sinG6#*&,$%(lambda|irG!\"\"#F(\"\"#%\"xGF(F(F(* &%$_C2GF(-%$cosGF+F(F(" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 40 "U 0:=rhs(dsolve(L(u(x))=-1/4*u(x),u(x)));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#U0G,&*&%$_C1G\"\"\"-%$cosG6#,$%\"xG#F(\"\"#F(F(*&%$_C2GF(-%$s inGF+F(F(" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 "lambda:='lambd a':assume(lambda>-1/4);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 44 " UP:=rhs(dsolve(L(u(x))=lambda*u(x),\{u(x)\}));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#UPG,&*&%$_C1G\"\"\"-%$expG6#*&%(lambda|irG#F(\"\"#% \"xGF(F(F(*&%$_C2GF(-F*6#,$F,!\"\"F(F(" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 79 " Now applying the boun dary conditions to each of these solutions. The result" }}{PARA 0 "" 0 "" {TEXT -1 84 " is a two linear equations for (_C1,_C2) whose co efficient matrix A is determined" }}{PARA 0 "" 0 "" {TEXT -1 66 " b y the code below. Eigenvalues are roots of det(A)=0. Defining" }} {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 14 " F= d et(A)" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 37 " the eigenvalue equation is F=0. " }}{PARA 0 "" 0 "" {TEXT -1 0 " " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 91 "A:=U->array([[coeff(BC1 (U),_C1),coeff(BC1(U),_C2)],[coeff(BC2(U),_C1),coeff(BC2(U),_C2)]]):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "with(linalg):" }}{PARA 7 "" 1 "" {TEXT -1 32 "Warning, new definition for norm" }}{PARA 7 "" 1 "" {TEXT -1 33 "Warning, new definition for trace" }}}{EXCHG {PARA 0 " > " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "FM:=det(A(UM));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#FMG,$*&-%$si nG6#*$,$%(lambda|irG!\"\"#\"\"\"\"\"#F/-%$cosGF)F/!\"#" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "F0:=det(A(U0));" }}{PARA 11 "" 1 " " {XPPMATH 20 "6#>%#F0G,$*&-%$cosG6##\"\"\"\"\"#F+-%$sinGF)F+F," }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "FP:=det(A(UP));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%#FPG,&*$-%$expG6#,$*$%(lambda|irG#\"\"\"\"\"# !\"\"F/F.*$-F(6#F+F/F0" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 87 " Since lambda are chosen so th at A is singular, finding the (_C1,_C2) which are in the" }}{PARA 0 " " 0 "" {TEXT -1 88 " nullspace can be found by solving the first row \+ of Ac = 0. Depending on the outcome of" }}{PARA 0 "" 0 "" {TEXT -1 87 " the previous analysis, the following code must be changed to find a ll eigenfunctions:" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 43 " psi are the nonnormalized eigenfunctions" }}{PARA 0 " " 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "A(UM) ;" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#-%'MATRIXG6#7$7$\"\"\"\"\"!7$,&-% $cosG6#*$,$%(lambda|irG!\"\"#F(\"\"#F(*&-%$sinGF.F(F0F3F2,&F6F(*&F,F(F 0F3F(" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 74 "NULLA:=U->nullspac e(array([[A(U)[1,1],A(U)[1,2]],[A(U)[1,1],A(U)[1,2]]])):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "NA:=NULLA(UM):" }}}{EXCHG {PARA 0 " > " 0 "" {MPLTEXT 1 0 42 "psi:=subs(\{_C1=NA[1][1],_C2=NA[1][2]\},UM); " }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%$psiG-%$sinG6#*&,$%(lambda|irG! \"\"#\"\"\"\"\"#%\"xGF-" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }} {PARA 0 "" 0 "" {TEXT -1 81 " To normalize them, the weight function \+ for the inner product must be specified:" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 41 " phi are the normalized eigenfun ctions." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "w:=x->1;" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%\"wG\"\" \"" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 44 "phi:=simplify(psi/int (psi*psi*w(x),x=0..1));" }}{PARA 11 "" 1 "" {XPPMATH 20 "6#>%$phiG,$*( -%$sinG6#*&,$%(lambda|irG!\"\"#\"\"\"\"\"#%\"xGF/F/,&*&-%$cosG6#*$F+F. F/-F(F6F/F/F7F-F-F+F.!\"#" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 11 "" 1 "" {TEXT -1 0 "" }}}}{MARK "22 0 0" 0 } {VIEWOPTS 1 1 0 1 1 1803 }