I don't really see the problem. I impicitiy differentiate the charpoly,
generating a function (i.e., the derivative). Imply want to evaluate the
function at a particular point.
In Maple, this is trivial:
with(linalg):
mat:=Matrix([[0,s_a*m_2,s_a*m_3],[s_o,0,0],[0,s_a.s_a]]);
cp:=charpoly(mat,lambda);
implicitdiff(cp,lambda,s_a);
subs(s_a=0.8,s_o=0.4,m_2=1.2,m_3=1.4,lambda=0.849,%);
yielding 0.834
(can do the same thing in Mathematica, and Gauss...)
Basically, all I (and students) need to be able to do is implicitly
differentiate a function, and then evaluate that derivative at a point
specific by known values of the variables in the derivative.
So, how does one do this in Maxima?
On 10/5/2011 12:50 PM, Richard Fateman wrote:
> On 10/5/2011 9:31 AM, Evan Cooch wrote:...
> ..
>
>> I think you should take rhs(part(sol,1)). and do the substitution.
>
> substituting 0.8 for x in d/dx ... makes no sense.
>