{VERSION 2 3 "APPLE_68K_MAC" "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 "" -1 256 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {CSTYLE "" -1 257 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 258 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 259 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 260 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {CSTYLE "" -1 261 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 262 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 263 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 264 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {CSTYLE "" -1 265 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 266 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 267 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 268 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {CSTYLE "" -1 269 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 270 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 271 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 272 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {CSTYLE "" -1 273 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 274 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 275 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 276 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 } {CSTYLE "" -1 277 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 278 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 279 "" 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 }{CSTYLE "" -1 280 "" 0 1 0 0 0 0 0 1 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 "" 0 256 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 1 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 }{PSTYLE "" 0 260 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 256 "" 0 "" {TEXT -1 41 "Differential Equations - - Guess-and-Check" }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 118 "The cell below illustrates how Maple can estimate the so lution to an initial valueproblem and the plot the estimate. " } {TEXT 256 16 "Evaluate it now." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 298 "with(plots):\n\nEndTime := \+ 10:\nInitialT := 100:\n\nIVP := \{diff(T(t), t) = 50 - T(t),\n \+ T(0) = InitialT\}:\n\nsolution := dsolve(IVP, \{T(t)\}, numeric):\n\np lt := display(\{odeplot(solution, [t, T(t)], 0..EndTime, color=blue)\} ):\n\ngraf := plot(50, 0..EndTime, 0..200, color=black):\n\ndisplay([p lt, graf]);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 " " {TEXT -1 49 "The cell above looks at the differential equation" }} {PARA 257 "" 0 "" {TEXT -1 2 "\n\n" }{TEXT 257 11 "T' = 50 - T" }} {PARA 0 "" 0 "" {TEXT -1 29 "\n\nwith the initial condition " }{TEXT 258 10 "T(0) = 100" }{TEXT -1 15 " and the range " }{TEXT 259 5 "0..10 " }{TEXT -1 17 " for the variable" }{TEXT 260 2 " t" }{TEXT -1 24 ". \+ The initial value for" }{TEXT 261 2 " T" }{TEXT -1 11 " is called " } {TEXT 262 9 "InitialT " }{TEXT -1 42 "and the end of the range for the variable " }{TEXT 263 1 "t" }{TEXT -1 12 " is denoted " }{TEXT 264 7 "EndTime" }{TEXT -1 121 ". You can change these values by changing th e obvious lines above. \n\nThe cell below looks at the differential \+ equation" }}{PARA 258 "" 0 "" {TEXT -1 2 "\n\n" }{TEXT 265 9 "y'' = -3 y" }{TEXT -1 1 " " }}{PARA 0 "" 0 "" {TEXT -1 33 " \n\nwith the initi al conditions " }{TEXT 266 9 "y(0) = 0 " }{TEXT -1 6 " and " }{TEXT 267 9 "y'(0) = 1" }{TEXT -1 17 " and the range " }{TEXT 268 4 "0..1 " }{TEXT -1 25 "0 for the time variable " }{TEXT 269 1 "t" }{TEXT -1 28 ". The initial values for " }{TEXT 270 1 "y" }{TEXT -1 7 " and \+ " }{TEXT 271 1 "y" }{TEXT -1 14 "' are called " }{TEXT 272 9 " Initi aly" }{TEXT -1 7 " and " }{TEXT 273 9 "Initialyp" }{TEXT -1 167 " r espectively and you can change these values by changing the obvious li nes above. . \n\nSpecifying the differential equation is a bit tricky . We use a new variable " }{TEXT 274 1 "v" }{TEXT -1 30 " to repres ent the derivative " }{TEXT 275 3 " y'" }{TEXT -1 13 " Thus, " } {TEXT 276 1 "v" }{TEXT -1 8 "' is " }{TEXT 277 2 " y" }{TEXT -1 119 "'' and the original (second order) differential equation is writ ten as a pair of (first order) differential equations" }}{PARA 259 " " 0 "" {TEXT -1 2 "\n\n" }{TEXT 278 15 "y' = v\nv' = -3y" }{TEXT -1 2 "\n\n" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 280 "with(plots):\n\nE ndTime := 10:\nInitialy := 0:\nInitialyp := 1:\n\nIVP := \{diff(y(t) , t) = v(t),\n diff(v(t), t) = -3 * y(t),\n y(0) = Initi aly,\n v(0) = Initialyp\}:\n\nsolution := dsolve(IVP, \{y(t), v (t)\}, numeric):\n\ndisplay(odeplot(solution, [t, y(t)], 0..EndTime)); " }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 62 "If you wanted, for example, to study the differential equation" }} {PARA 260 "" 0 "" {TEXT -1 2 "\n\n" }{TEXT 279 16 "y'' = -3y -0.1y'" } }{PARA 0 "" 0 "" {TEXT -1 25 "\n\nyou would rewrite it as" }}{PARA 0 " " 0 "" {TEXT -1 2 "\n\n" }{TEXT 280 22 "y' = v\nv' = -3y - 0.1v" }} {PARA 0 "" 0 "" {TEXT -1 29 "\n\nas shown in the cell below." }}{PARA 0 "" 0 "" {TEXT -1 0 "" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 293 " with(plots):\n\nEndTime := 10:\nInitialy := 0:\nInitialyp := 1:\n\nI VP := \{diff(y(t), t) = v(t),\n diff(v(t), t) = -3 * y(t) - 0.1 * v(t),\n y(0) = Initialy,\n v(0) = Initialyp\}:\n\nsol ution := dsolve(IVP, \{y(t), v(t)\}, numeric):\n\ndisplay(odeplot(solu tion, [t, y(t)], 0..EndTime));" }}}}{MARK "0 0 0" 41 }{VIEWOPTS 1 1 0 1 1 1803 }