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Replies: 2   Last Post: Feb 2, 2013 1:15 AM

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 Louis Talman Posts: 5,100 Registered: 12/27/05
Posted: Jan 31, 2013 8:45 PM

On Wed, 30 Jan 2013 20:05:12 -0700, jeremy <j.witoslawska@gmail.com> wrote:

> Hi,
> i'm new in Mathematica and i've a project to do. i've to find at what
> time 90% of the steady state concetration of C is achieved. and soo far
> i have something like that, for 3 different k values:
>
> With[{k = 0.3}, eqn1s = 0 == k (1/2 - z[t]) (1/3 - z[t])];
> With[{k = 0.6}, eqn2s = 0 == k (1/2 - z[t]) (1/3 - z[t])];
> With[{k = 0.9}, eqn3s = 0 == k (1/2 - z[t]) (1/3 - z[t])];
> Evalute[{eqn1s, eqn2s, eqn3s}]
> NSolve[Evaluate[{eqn1s, eqn2s, eqn3s}], z[t]]
>
> and what i get in NSolve is supposedly be the steady state, but i don't
> know how to find this 90% and my profesor told me that i could try do
> this with DSolve, but something doesn't work. i hope that someone will
> be able to help me with this.
>
> Thanks
>

The purpose of this list isn't that of solving people's homework problems
for them.

If your professor wanted someone to tell you how to work the problem,
don't you think *he* would've told you how to work it?

--
--Louis A. Talman
Department of Mathematical and Computer Sciences
Metropolitan State University of Denver

<http://rowdy.msudenver.edu/~talmanl>

Date Subject Author
1/31/13 Louis Talman
2/2/13 Alexei Boulbitch