Laplace Trasform system of differential equation
- To: mathgroup at smc.vnet.net
- Subject: [mg122022] Laplace Trasform system of differential equation
- From: elos <marusik_92 at inbox.ru>
- Date: Sun, 9 Oct 2011 03:53:07 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
where I made a mistake? I need to solve the system of differential equations using Laplace transforms and the plots. Solve happened, but no graphics.
odeSys = {x'[t] - x[t] + y[t] == 0,
y'[t] - x[t] - y[t] == 0,
z'[t] - x[t] - y[t] - 2*z[t] == 0}
eq1 = LaplaceTransform[odeSys, t, s]
eq2 = Solve[eq1, {LaplaceTransform[x[t], t, s],
LaplaceTransform[y[t], t, s],
LaplaceTransform[z[t], t, s]}]
sol1 = Map[InverseLaplaceTransform
[#, s, t] &, eq2, {3}] /. {x[0] -> 1, y[0] -> 1, z[0] -> 1}
sol2 = DSolve[{odeSys, x[0] == 1, y[0] == 1, z[0] == 1},
{x[t], y[t], z[t]}, t] // Simplify
ParametricPlot[Evaluate[{x[t], y[t], z[t]} /. sol1],
{t, 0, 1}, PlotStyle -> {Hue[0.5], Thickness[0.01]}]
Here is system of differential equations: x'[t]=x[t]-y[t]
y'[t]=x[t]+y[t]
z'[t]=x[t]+y[t]+2*z[t]