The file is attached.

Download err.mw

The command 'coeff' doesn't work.

Hi,

    This is not an answer. I can't ask question, since I can't add any 'tags'! This problem appeared long time ago, but I hadn't solved it until now. So I ask here.

    I have a question about the function coeffs(). I don't know why it cann't get coefficients for me.

question.mw

Thanks.

I am sorry. There is no 'tag' button on my computer, so I can't ask question here. I don't know the reason.

So I ask here. Now, my real question is:

sum(subs(x = 0, diff(x^2, x $ k)), k = 1 .. 2);

                               0

subs(x = 0, diff(x^2, x $ 2));
                               2

I think the first result should be 2, but it gives me 0.

Thanks in advance.

Hi,

      I need to compute something involved with the pseudo differential operators.

https://en.wikipedia.org/wiki/Pseudo-differential_operator

Specifically, I need to calculate the inverse of a pseudo differential operator, the multiplication of two pseudo differential operators, and the n-th root of a pseudo differential operator. 

I don't know whether Maple could handle these. 

Thanks.

This is my original question, but I can't ask, so I put it here.

I have a system of pde, and it's hard to solve.

But I want to find the type of solutions which are polynomials of degree n of the several independent variables.

Is it possible using 'pdsolve'? Or there are some other commands in Maple to do that?

Thanks!