I try to draw a graph:
ClearAll[k, r, n]
k = 20
r = .8
Manipulate[
psol = DSolve[{p'[t] == r*p[t] (1 - p[t]/k), p[0] == n}, p[t], t];
Plot[ psol[t] , {t, -10, 10} ], {n, 0, 1}]
but I get an error:
Inverse functions are being used by Solve, so some solutions may not be found; use Reduce for complete solution information.
The message is warning that inverse functions are being used by Solve, so some solutions may not be found
You can ignore it if you want
ClearAll[k, r, n]
k = 20
r = .8
Manipulate[
psol=Quiet[DSolve[{p'[t]==r*p[t] (1-p[t]/k),p[0]==n},p[t],t]];
Plot[p[t]/.psol,{t,-10,10}],
{{n,0,"n"},0,1,Appearance->"Labeled"}
]
Or it might be better to turn off that one messaage
Manipulate[
psol=DSolve[{p'[t]==r*p[t] (1-p[t]/k),p[0]==n},p[t],t];
Plot[p[t]/.psol,{t,-10,10}],{{n,0,"n"},0,1,Appearance->"Labeled"}
,Initialization:>
{
k=20;
r=.8;
Off[Solve::ifun]
}
]
see ref/message/Solve/ifun for more information on this message
Quiet[] to turn off a single message locally: Quiet[Solve[y == x Exp[x], x], Solve::ifun].
$\endgroup$
NDSolve.
$\endgroup$
DSolve, move that to the Initialization: Manipulate[ Plot[sol[n, t], {t, -10, 10}, PlotRange -> {0, 20}], {{n, 0}, 0, 1, 0.01, Appearance -> "Labeled"}, Initialization :> {k = 20; r = 4/5; sol[n_, t_] = p[t] /. DSolve[{p'[t] == r*p[t] (1 - p[t]/k), p[0] == n}, p, t][[1]] // Quiet}]
$\endgroup$