On Wed, Jun 2, 2010 at 8:08 PM, Leo Butler <l.butler at ed.ac.uk> wrote:
>
>
> On Wed, 2 Jun 2010, ultrokevjr wrote:
>
>
> < very sorry about mistake in the former post(eval the result of solve will
> trigger the problem, however, eval together with solve express just works
> like a charm):
> <
> <
> eq1:(y[i]-y[1])/(y[1]-y[2])=y[1]*(1+K[L]*rho*y[2])/y[2]/(1+K[L]*rho*y[1]);
> <
> eq2:(y[i]-y[1])/(y[2]-y[f])=y[1]*(1+K[L]*rho*y[f])/y[f]/(1+K[L]*rho*y[1]);
> < solve([eq1,eq2],[y[1],y[2]]); --------- stumbled here
>
> I see, Maxima does spend a long time on this computation.
> Note that Maple does not compute a solution, it just tells
> you how it would compute a solution.
>
> Here is an idea:
>
> eq1:(yi-y1)/(y1-y2)=y1*(1+KL*rho*y2)/y2/(1+KL*rho*y1);
> eq2:(yi-y1)/(y2-yf)=y1*(1+KL*rho*yf)/yf/(1+KL*rho*y1);
> solve(eq1,y1);
> subst(%,eq2);
> rat(%);
> solve(%,y2), programmode=false;
>
> This produces a messy, long formula for y2.
>
Understand now, thanks very much! :)