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Clear["Global`*"]
Clear["`*"]
sol = NDSolve[{y1'[t] == y2[t] y3[t], y2'[t] == -y1[t] y3[t],
y3'[t] == -0.51 y1[t] y2[t], y1[0] == 0, y2[0] == 1,
y3[0] == 1}, {y1, y2, y3}, {t, 10}]
Plot[Evaluate[sol /. %], {t, 0, 10}]
NDSolve::deqn: Equation or list of equations expected instead of True in the first argument {(y1^\[Prime])[t]==y2[t] y3[t],(y2^\[Prime])[t]==-y1[t] y3[t],True,y1[0]==0,y2[0]==1,y3[0]==1}.
ReplaceAll::reps: {NDSolve[{(y1^\[Prime])[t]==y2[t] y3[t],(y2^\[Prime])[t]==-y1[t] y3[t],True,y1[0]==0,y2[0]==1,y3[0]==1},{y1,y2,y3},{t,10}]} is neither a list of replacement rules nor a valid dispatch table, and so cannot be used for replacing.
NDSolve::dsvar: 0.0002042857142857143` cannot be used as a variable.
ReplaceAll::reps: {NDSolve[{(y1^\[Prime])[0.000204286]==y2[0.000204286] y3[0.000204286],(y2^\[Prime])[0.000204286]==-y1[0.000204286] y3[0.000204286],True,y1[0]==0,y2[0]==1,y3[0]==1},{y1,y2,y3},{0.000204286,10}]} is neither a list of replacement rules nor a valid dispatch table, and so cannot be used for replacing.
NDSolve::dsvar: 0.0002042857142857143` cannot be used as a variable.
General::stop: Further output of NDSolve::dsvar will be suppressed during this calculation.
ReplaceAll::reps: {NDSolve[{(y1^\[Prime])[0.000204286]==y2[0.000204286] y3[0.000204286],(y2^\[Prime])[0.000204286]==-1. y1[0.000204286] y3[0.000204286],True,y1[0.]==0.,y2[0.]==1.,y3[0.]==1.},{y1,y2,y3},{0.000204286,10.}]} is neither a list of replacement rules nor a valid dispatch table, and so cannot be used for replacing.
General::stop: Further output of ReplaceAll::reps will be suppressed during this calculation.
Clear["`*"]
sol = NDSolve[{y1'[t] == y2[t] y3[t], y2'[t] == -y1[t] y3[t],
y3'[t] == -0.51 y1[t] y2[t], y1[0] == 0, y2[0] == 1,
y3[0] == 1}, {y1, y2, y3}, {t, 10}]
Plot[Evaluate[sol /. %], {t, 0, 10}]
NDSolve::deqn: Equation or list of equations expected instead of True in the first argument {(y1^\[Prime])[t]==y2[t] y3[t],(y2^\[Prime])[t]==-y1[t] y3[t],True,y1[0]==0,y2[0]==1,y3[0]==1}.
ReplaceAll::reps: {NDSolve[{(y1^\[Prime])[t]==y2[t] y3[t],(y2^\[Prime])[t]==-y1[t] y3[t],True,y1[0]==0,y2[0]==1,y3[0]==1},{y1,y2,y3},{t,10}]} is neither a list of replacement rules nor a valid dispatch table, and so cannot be used for replacing.
NDSolve::dsvar: 0.0002042857142857143` cannot be used as a variable.
ReplaceAll::reps: {NDSolve[{(y1^\[Prime])[0.000204286]==y2[0.000204286] y3[0.000204286],(y2^\[Prime])[0.000204286]==-y1[0.000204286] y3[0.000204286],True,y1[0]==0,y2[0]==1,y3[0]==1},{y1,y2,y3},{0.000204286,10}]} is neither a list of replacement rules nor a valid dispatch table, and so cannot be used for replacing.
NDSolve::dsvar: 0.0002042857142857143` cannot be used as a variable.
General::stop: Further output of NDSolve::dsvar will be suppressed during this calculation.
ReplaceAll::reps: {NDSolve[{(y1^\[Prime])[0.000204286]==y2[0.000204286] y3[0.000204286],(y2^\[Prime])[0.000204286]==-1. y1[0.000204286] y3[0.000204286],True,y1[0.]==0.,y2[0.]==1.,y3[0.]==1.},{y1,y2,y3},{0.000204286,10.}]} is neither a list of replacement rules nor a valid dispatch table, and so cannot be used for replacing.
General::stop: Further output of ReplaceAll::reps will be suppressed during this calculation.
