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Torsten
Posts:
1,717
Registered:
11/8/10


Re: (yet unsolved) how to Solve coupled ODEs
Posted:
Feb 12, 2013 11:07 AM


"Henry" wrote in message <kfb8m3$mom$1@newscl01ah.mathworks.com>... > Problem not yet solves, any helps please?
Just compare line for line:
global a b c d e a=...; b=...; c=...; d=...; e=...; [t,y] = ode45(@odeeqns, [0 3], [1 1]); function dyds = odeeqns(s,y) global a b c d e dyds = zeros(2,1) dyds(1,1) = 1/y(1) *(y(2)*(d+s /y(2))a *y(1)*sqrt(y(1)^2+(e+y(2))^2)); dyds(2,1) = (y(2)*(b+y(2))*sqrt(y(1)^2+(e+y(2))^2))/y(1)y(2)/s  c;
Best wishes Torsten.
If you start with s=0 as I suggested in the call to ode45, you will get problems in the evaluation of dyds(2,1) because of the term y(2)/s (division by zero). Please supply the values of the parameters a,b,c,d and e, the interval of integration and the error message you received.
Best wishes Torsten.



