ode45 Error not working

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Bob
Bob 2016-7-28
评论： Torsten 2016-7-29
Use ode45 to overlay plots of solutions to this differential equation with y (0) = c for c ranging from 0 to 1 in steps of 0:1.
equation: 5*y*(1-y)-(1+(1/2)*sin(2*pi*t));
Attempted code:
syms y(t);
for c = 0:0.1:1
f = @(t, y) 5*y*(1-y)-(1+(1/2)*sin(2*pi*t));
[t,y] = ode45(f, [0,0], c)
end
Error:
Error in ode45 (line 115)
odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
Error in Project_3 (line 33)
[t,y] = ode45(f, [0,0], c);
If I change the 2nd 0 to 1 in the ode45 it works but my question asks for it at y(0).
  1 个评论
Torsten
Torsten 2016-7-29
If you set
tspan=[0,0]
as you do, you try to integrate from tstart=0 to tend=0 which does not make sense.
Best wishes
Torsten.

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采纳的回答

Walter Roberson
Walter Roberson 2016-7-28
Do not use for to calculate at those time steps. You cannot use the ode* functions to calculate a single individual time step. Instead, create a vector holding the timesteps you want to be evaluated at and pass that vector in the tspan argument position to ode45 -- a single call, not a loop.

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