Mathematica入门习题[21]–解微分方程组

第二十一题--解微分方程组

Clear["Global`*"]
sol = NDSolve[{y1'[x] == y2[x]*y3[x], y2'[x] == -y1[x]*y3[x],
y3'[x] == -.51*y1[x]*y2[x], y1[0] == 0, y2[0] == 1,
y3[0] == 1}, {y1[x], y2[x], y3[x]}, {x, 0, 12}];
Plot[Evaluate[{y1[x] /. sol[[1, 1]], y2[x] /. sol[[1, 2]],
Evaluate[y3[x] /. sol[[1, 3]]]}], {x, 0, 12},
PlotLegends -> Automatic, PlotRange -> All]