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Topic: Solving a system of three coupled linear diff equations
Replies: 9   Last Post: Jan 15, 2014 2:15 AM

 Messages: [ Previous | Next ]
 Torsten Posts: 1,631 Registered: 11/8/10
Re: Solving a system of three coupled linear diff equations
Posted: Jan 14, 2014 9:44 AM

"Peter " <c4359385@drdrb.com> wrote in message <lb3hr5\$e12\$1@newscl01ah.mathworks.com>...
> Hm, this gives me
>
> Error using char
> Cell elements must be character arrays.
>
> Error in dsolve>mupadDsolve (line 279)
> if isvarname(char(args{end}))
>
> Error in dsolve (line 186)
>
> Error in SpinLifetimes (line 23)
> Y = dsolve({diff(M1) == -p1*M1+p2*M2, diff(M2) == -(p2+p3)*M2+p1*M1+p4*M3, diff(M3)
> == -p4*M3+p3*M2}, {M1(0) == 1, M2(0) == 0, M3(0) ==0});
>
> I don't really see what that means in this context, why does it need something to be a character?

Maybe like this:
p1 = 0.05;
p2 = 0.05;
p3 = 0.05;
p4 = 0.05;
syms M1(t) M2(t) M3(t)
Y = dsolve(diff(M1) == -p1*M1+p2*M2, diff(M2) == -(p2+p3)*M2+p1*M1+p4*M3, diff(M3) == -p4*M3+p3*M2, M1(0) == 1, M2(0) == 0, M3(0) ==0)

Best wishes
Torsten.

Date Subject Author
1/14/14 Peter
1/14/14 Torsten
1/14/14 Peter
1/14/14 Torsten
1/14/14 Peter
1/14/14 Torsten
1/14/14 Peter
1/14/14 Torsten
1/14/14 Peter
1/15/14 Torsten