I have a system of PDE's - 14 equations.  I am trying to solve for 9 functions in terms of other functions.  I thought I was doing this correctly.  I have:

How can I check if an assignment already exits?  I have a process that assigns an eqn name to the coefficients of a polynomial.  I have a number of different of polynomials that I want to do this assignment.  I have the following process:

> EqnCoeff := proc (Poly)
local n, k;
global EQN;
n := degree(Poly);
for k from 0 to n do
EQN[k] := coeff(Poly, phi1, k)
end do
end proc;

(my polynomials have indeterminate phi1)

Hi everyone,

I am having some trouble separting terms in a pretty gnarly PDE.  I have a fairly complicated 2+1 PDE with auxillary conditions that I am trying to solve with a formal separation of variables approach.  I have a PDE that looks like this:

I am trying to expand a derivative using the chain rule and sitching the order of differentiation.

I am looking at some asymptotic expansions of a PDE and need to do some differentiating with complex conjugates.  Specifically, I have a number of functions that are functions of both z and conjugate(z), they may look something like:

S -> (z,conjugate(z),xi)

I would like to take the conjugate(z) derivative,

S[conjugate(z)]  = diff(S(z,conjugate(z),xi),conjugate(z)),

but I get:

D₁S(z,conjugate(z),xi) + D₂S(z,conjugate(z),xi)(-\frac{conjugate(z)}{z} - \frac{abs(1,z)}{signum(z)}