restart;

with(DETools, diff_table);

kB := 0.138064852e-22;

R := 287.058;

T := 293;

p := 101325;

rho := 0.1e-2*p/(R*T);

vr := diff_table(v_r(r, z));

vz := diff_table(v_z(r, z));

eq_r := 0 = 0;

eq_p := (vr[z]-vz[r])*vr[] = (vr[]*(vr[r, z]-vz[r, r])+vz[]*(vr[z, z]-vz[z, r]))*r;

eq_z := 0 = 0;

eq_m := r*vr[r]+r*vz[z]+vr[] = 0;

pde := {eq_m, eq_p};

IBC := {v_r(1, z) = 0, v_r(r, 0) = 0, v_z(1, z) = 0, v_z(r, 0) = r^2-1};

sol := pdsolve(pde, IBC, numeric, time = z, range = 0 .. 1);

what am I doing wrong?

it's telling me: Error, (in pdsolve/numeric/par_hyp) Incorrect number of boundary conditions, expected 3, got 2
but i did just as in the example :-/

I have a vector of dimension n with each component being an equation of a linear system.

Can maple convert this Vector to a Matrix-Vector form with the matrix being constant coefficients?

is there a built in function which calculates the radical of a number?

e.g. 54=2*3^3

rad(54)=2*3=6

I just wanted to ask whether one can get out of the expansion

(D-f(x))@@2(g)(x)=(D@@2)(g)(x)-(D((f(x))(g)))(x)-((f(x))(D(g)-(f(x))(g)))(x)

the intended result

(D@@2)(g)(x)-D(f*g)(x)-f(x)*D(g)(x)+f(x)^2*g(x)

I'm just using it this way:

with(QDifferenceEquations):
QPochhammer(-1,5,10)

Error, (in QDifferenceEquations:-QPochhammer) wrong type of arguments

Am I doing something terribly wrong???