so I'm trying this:

restart;

sigma := 0.143e-18;

l_0 := 1.87;

l0 := 1.87;

roll := rand(0 .. 25.0);

f_gauss := proc (x) options operator, arrow; exp(-(1/2)*x^2/`σ_x`^2)/sqrt(2*Pi*`σ_x`^2) end proc;

f_norm := proc (dx) options operator, arrow; int(f_gauss(x), x = -(1/2)*dx .. (1/2)*dx) end proc;

sol_gauss := proc (mix) options operator, arrow; evalf(eval(-ln((int(f_gauss(x)*exp(-2*sigma*N2O*sqrt((1/4)*l_0^2-x^2)), x = -(1/2)*dx .. (1/2)*dx))/f_norm(dx))/(sigma*N2O), [N2O = 0.25e20*mix/100])) end proc;

for ii to 10 do

a := roll();

eval(sol_gauss(a), [dx = l_0, `σ_x` = l0])

end do

S:=...+a^4*b*c*x^2+...

So I know it is possible to collect for example any letter collect(S,x)

But I want to collect in particular for an entire product in this case

e.g. collect(S,a^4*b*c)

This obviously doesnt work but is it possible to get it working somehow?

I have a system of equations e.g.

A^2+B*A+C=0

where A,B,C are Matrices and I want to solve for A.

Sure I can write every equations in brakets [..=0], but isn'T it possible to just use the matrix notation?

vz := 2*(-eta^2+1);

D_im := .22;

r0 := 1;

pde := diff(vz*Y(eta, z), z)-D_im*((diff(eta*(diff(Y(eta, z), eta)), eta))/eta+diff(Y(eta, z), `$`(z, 2)))/r0 = 0;

pde := expand(%);

ibc := [Y(1, z) = 0, (D[1](Y))(0, z) = 0, Y(eta, 0) = 1, (D[2](Y))(eta, 0) = 0];

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

pds := sol:-value(z = 0, output = listprocedure);

sol:-plot(z = 0.1e-3, numpoints = 50, color = blue, view = 0 .. 1)

So I was trying to solve this conservation equation for the radial coordinate eta and the z coordinate being treated as time. The flow is in z direction. Now unfortunately it is diverging. Not sure why though. What am I doing wrong?

Is it possible to subscript within a plot?

for example I have

this in principle is what I want but, the N is cursive while is O is not (and it's a bit shifted to the right, not right next to the [2] !???

Also I didnt find the meanings of mi(),mn(),mo(),mfenced()... in the help documentation which I stumbled across while googling.

for example in this case:

what do I need them for since without the mi it doesnt work?!

Is it possible to use latex notation within the plot options for more convenience?

BTW: When plotting a .ps or .eps the plotting device takes over all the features (like the examples above) but when using png instead it just prints the code behind it ( for example the `#mover(mi("x"),mi("~"))` ) and not would it should lead to