{VERSION 6 0 "IBM INTEL LINUX" "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 }{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 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 0 "" 0 "" {TEXT -1 50 "LaplaceClass_A11.mws\nTue \+ Oct 11 09:20:59 MDT 2005\n" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 8 "restart;" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 21 "with(plots, display):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 34 "step := (t,A) -> Heaviside(t-A); " }{TEXT -1 27 "Our text's \"step\" function." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 47 "RHS := t -> (1 - step(t,1))*2*t + 2*step(t,1); " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "TRG := 0..4:" }}}{EXCHG {PARA 0 "> " 0 " " {MPLTEXT 1 0 25 "P_RHS := plot(RHS, TRG): " }{TEXT -1 37 "Save drivi ng-function plot for later." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 18 "#display(P_RHS); " }{TEXT -1 52 "Checking if the driving function 's entered properly." }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 70 "The differential equation: y'' + y = RHS with \+ y(0) = 0 and y'(0) = 1." }}{PARA 0 "" 0 "" {TEXT -1 1 " " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 36 "DEA := (D@@2)(y)(t) + y(t) = RHS(t) ;" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 30 "Set up the initial conditions:" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }} }{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 31 "WIMPY := y(0) = 0, D(y)(0) \+ = 1:" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 48 "Put together the argument sequence for \"dsolve\":" }}{PARA 0 " " 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 20 "IVP \+ := \{DEA, WIMPY\}:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 13 "VARS \+ := y(t):" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "CARGO := IVP, V ARS:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 "SOLN := dsolve(CARG O); " }{TEXT -1 32 "Solve the initial-value problem." }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 47 "Recover t he solution for plotting and checking:" }}{PARA 0 "" 0 "" {TEXT -1 0 " " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 31 "yy := unapply( rhs(SOLN ), t): " }{TEXT -1 33 "Get solution as Maple function yy" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 40 "P_SOLN := plot(yy, TRG, colour=BLAC K): " }{TEXT -1 18 "Plot the solution." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 25 "display(P_RHS, P_SOLN); " }{TEXT -1 39 "Solution and driving function together." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 56 "########################################################" }}} {EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 53 "He re we check the piecewise formula for the solution:" }}{PARA 0 "" 0 " " {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 14 "assume(u \+ < 1);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "assume(v > 1); " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "yy(u);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 6 "yy(v);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 57 "############## ###########################################" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}} }{MARK "31" 0 }{VIEWOPTS 1 1 0 1 1 1803 1 1 1 1 }{PAGENUMBERS 0 1 2 33 1 1 }