Re: Numerical solution to a simple exponential equation

WOW! That was quick, Boris! It almost looks as if you sent your answer
before I asked the question! :-)
And it even works (I have already tried it)! 
I also found a way to get the other solution.

Thank you very much!

--Virgil
P.S. I am replying to the list in case someone else may want to know.
It seems that Maxima's initial help/tutorial does not address the issue
of how to obtain numerical solutions when explicit symbolic solutions
are not available.


--- Boris Veytsman <borisv@lk.net> wrote:
> > From: Virgil <virgilinux at yahoo>
> > Date: Tue, 3 Jul 2001 14:55:49 -0700 (PDT)
> 
> > 
> > (C1) h(x):=x*exp(-x);
> > (C2) solve(h(x)=1/4);
> > 				      x
> > 				    %E
> > (D2) 			       [x = ---]
> > 				     4
> > 
> > Of course, Maxima is correct to say that x=exp(x)/4 "solves" the
> above
> > equation, but that is not really what one is looking for.
> > 
> > Numerically, one can verify that x=0.36 and x= 2.15 would make
> > h(x)=0.25.
> > 
> > But, how to get Maxima to give this answer??
> > 
> 
> 
> (C191) load(newton);
> 
> (D191)		      /usr/lib/maxima-5.6/share/newton.mc
> (C192) NEWTON(x*exp(-x)-1/4,x,0,1.e-6);
> 
> (D192)			       0.35740290341774


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