First assign the Matrix to a variable, say M.  Then

eval(M)

I'd prefer not to assign to f and use the two-argument form of eval:

eval(M, f = ((x,y) -> x+y))

Note: edited to fix typo per Mario's feedback (below).

First assign the Matrix to a variable, say M.  Then

eval(M)

I'd prefer not to assign to f and use the two-argument form of eval:

eval(M, f = ((x,y) -> x+y))

Note: edited to fix typo per Mario's feedback (below).

Only the second assume is necessary. Additional calls to assume with the same base expression replace preexisting assumptions.  Use ?additionally to apply additional assumptions.

Only the second assume is necessary. Additional calls to assume with the same base expression replace preexisting assumptions.  Use ?additionally to apply additional assumptions.

X := [25, 30, 35];
Y := [25, 30, 35];
Matrix(3,3, (i,j) -> f(X[i],Y[j]) );
                                     [f(25, 25)    f(25, 30)    f(25, 35)]
                                     [                                   ]
                                     [f(30, 25)    f(30, 30)    f(30, 35)]
                                     [                                   ]
                                     [f(35, 25)    f(35, 30)    f(35, 35)]

X := [25, 30, 35];
Y := [25, 30, 35];
Matrix(3,3, (i,j) -> f(X[i],Y[j]) );
                                     [f(25, 25)    f(25, 30)    f(25, 35)]
                                     [                                   ]
                                     [f(30, 25)    f(30, 30)    f(30, 35)]
                                     [                                   ]
                                     [f(35, 25)    f(35, 30)    f(35, 35)]

TF := (1+s*D)/(A*s^2 + B*s + C):
(n,d) := (numer,denom)(TF):
K := tcoeff(d,s);
                                    K := C

n/(K*(expand(d/K)));
                                   1 + s D
                              ------------------
                                /   2          \
                                |A s    B s    |
                              C |---- + --- + 1|
                                \ C      C     /

TF := (1+s*D)/(A*s^2 + B*s + C):
(n,d) := (numer,denom)(TF):
K := tcoeff(d,s);
                                    K := C

n/(K*(expand(d/K)));
                                   1 + s D
                              ------------------
                                /   2          \
                                |A s    B s    |
                              C |---- + --- + 1|
                                \ C      C     /

What do you want the animation to do?  That is, what is changing with time?

It is important to use parentheses to group any products, &// has a higher binding strength than * or /, see ?operators,precedence
You can avoid that by using the functional form
 

`&//`(R1+R2, 1/s/C);

It is important to use parentheses to group any products, &// has a higher binding strength than * or /, see ?operators,precedence
You can avoid that by using the functional form
 

`&//`(R1+R2, 1/s/C);

Use the ?DynamicSystems package:

TF := (1+s*D)/(A*s^2 + B*s + C):
with(DynamicSystems):
zpk := ZeroPoleGain( TF );
                      zpk := Zero Pole Gain (continuous)

zpk:-z;
                                   [[- 1/D]]

zpk:-p;
               [         2         1/2          2         1/2 ]
               [   B - (B  - 4 A C)       B + (B  - 4 A C)    ]
               [[- -------------------, - -------------------]]
               [           2 A                    2 A         ]

zpk:-k;
                                     [D/A]

Use the ?DynamicSystems package:

TF := (1+s*D)/(A*s^2 + B*s + C):
with(DynamicSystems):
zpk := ZeroPoleGain( TF );
                      zpk := Zero Pole Gain (continuous)

zpk:-z;
                                   [[- 1/D]]

zpk:-p;
               [         2         1/2          2         1/2 ]
               [   B - (B  - 4 A C)       B + (B  - 4 A C)    ]
               [[- -------------------, - -------------------]]
               [           2 A                    2 A         ]

zpk:-k;
                                     [D/A]

They are used in the simulation to handle events, etc.  As such they need to be properly initialized, however, they aren't necessarily relevant for the system equations of a particular configuration.

They are used in the simulation to handle events, etc.  As such they need to be properly initialized, however, they aren't necessarily relevant for the system equations of a particular configuration.