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Janice Robertson
06/07/99 8:06pm

Hello,

I am trying to solve a system of non-linear differential equations in Mathematica, but I am encoutering a multitude of problems and error messages.

I have tried to enter it as follows:

sol1 = NDSolve[{v'[t]==(-1/c) (ina[t] +ik1[v] +ist),
m'[t]==am[v]-m[t]*(am[v]+bm[v]),
h'[t]==ah[v]-h[t]*(ah[v]+bh[v]),
j'[t]==aj[v]-j[t]*(aj[v]+bj[v])},
{v[0]==-80, m[0]==0, h[0]==1, j[0]==1},
{v[t], m[t], h[t], j[t]}, {t, 0, 100}]

where c, and ist are constants, and ik1, a[m, h, j], b[m, h, j] are elaborate functions which depend on v, and ina requires the solutions of m, h, and j (implying that v does as well).

The error message that I receive when I enter it exactly as above is:

NDSolve::dsfun : v[0]==-80 cannot be used as a function.

I was wondering if I entered to equations incorrectly, or maybe earlier in the program, I defined v as a function already.

Could anybody please suggest some possibilities of solving these equations.

Thanks    

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Subject (listing for 'diffeq's')
Author Date Posted
diffeq's Janice Rober... 06/07/99 8:06pm
Re: diffeq's Forum Modera... 06/08/99 2:52pm
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