Hiya, I'm trying to solve this pde in Maple:

> PDE:= diff(c(z,t),t) = k*diff(c(z,t),z$2) + w*diff(c(z,t),z);

where k, w are constants, but I don't know how to apply the boundary conditions:

c(0,t)=0 and 0=k*diff(c(z,t),z$2) + w*diff(c(z,t),z) at z=h

and initial condition c=f(z) at t=0

I know by hand you would solve by separating variables, but is there an equivalent method in Maple?

Eventually I want to plot c(z) for given times to show how the solution evolves... but one thing at a time!

Thank you everyone for all your help.
However, what I am leading up to in my research requires
that I overcome the following hurdle.
Let p[m] represent an unspecified function of three variables,
e1, e2, and e3. (In reality, the explicit formula for the
function is known, but I will not use that formula.)
m is an index. So, p[1], p[2], p[3] etc are different functions of e1, e2, e3.
I need to program an operator, T, which acts on p[m] and
returns - symbolically -
T(p[m]) = 1*e1*diff(p[m],e1) + 2*e2*diff(p[m],e2)
+ 3*e3*diff(p[m],e3)
In case anyone has guessed already, T has gone under such

The third example on the Plot Tickmarks and Gridlines help page - ?plot,tickmarks(tickmarks) - shows how to put labels at specific locations on a plot axis. But I couldn't find anything in the help pages about altering their font. However by changing the labels to names (enclose in left quotes, instead of double quotes) their font could be set using the axesfont option.

Perhaps something could be added to the example mentioned above. In the longer run though, all the help pages for plots need to be re-written: at present they resemble an untidy scrapbook.

J. Tarr

What would be an effective way to code a sequence of numbers Y(t):=Poisson random variable with mean X(t) and X(t):=M+phi*X(t-1)+alpha*(Y(t-1)-X(t-1)) for 0<alpha<phi<1, M>0? Thanks.

I am currently studying the phase portrait a differential equation:
diff(y(t), t, t) = -piecewise((diff(y(t), t))*y(t) <><>
0 <><><>
Initial conditions are:
y(0) = 1; , diff(y(0), t) = 0;
The phase portrait plots diff(y(t),t) with respect to y(t).
I achieved the phase portrait using Simulink; with a few gain blocks, a switch and a X-Y scope, easily enough.
When i was done, i wondered if i could analyze the equation with a more mathematical approach. I decided to try and plot the phase portrait using Maple 11. I have tried various commands to solve the differential equation with Maple 11 but so far i have confused myself.

The command
> contourplot(-1,x=0..1,y=0..1,contours=[0],filled=true);
is supposed to fill the whole space with red (color for negative values) but it does nothing
this is also problem once I need to define a piecewise function which is constant according to some condition, e.g.
> f:=(x,y)->piecewise(x>1/2,x*y,-1);
> contourplot(f(x,y),x=0..1,y=-1..1,contours=[0],filled=true);
this should fill the entire half plane x>1/2 with red, it fills only part of the first quadrant...

The simpliest version of my problem is this:
> f:=(x,y)->fsolve(sin(x+y+z)=1,z)
> f(5,5);
still ok but now:
> plot(f(x,5),x=5..10);
sais: "Error, (in fsolve) x is in the equation, and is not solved for"
it seems as Maple would not first evaluate x:=5 and then solve f(x) :'(

Hello!
How can I solve a linear equation which depends on two parameters (a,b) for which the assumption a^2 + b^2 = 1 shall hold.
This does not work by writing assume or assuming.
The problem has the following form:
tau := f(a,b) -> eigenvalues of a matrix U = U(a,b)
M := U - tau*Id = M(tau,a,b) = M(a,b)
find the kernel of M (eigenvectors of U) and simplify using a^2 + b^2 = 1.
I do not want to write down the exact matrix and hope that this information is enough. If not, I will take some time to write it down.
Greetings,
yadaddy.

I have a Maple 11 Document and I'd like to print it. It currently has a couple graphs and text and mathematic equations on it. However, when I print the document the fonts are all jacked up. Minus signs show as vertical lines, fonts are on top of each other and it just looks terrible. I've tried exporting to HTML but the image quality is terrible on everything that wasn't entered as text. No apparent option to use anything but gifs which are the worst possible thing to use for quality.
Any suggestions would be greatly appreciated.
glenn

This is a new thread to continue a discussion that started under the topic

What is wrong with my program? (by resolvent).
Here are the first three responses:

Does anybody know how can I plot 3D chart with gridlines for Axes style set to boxed?
and the second question:
How can I plot 3D chart with 3D bars?

Hi everyone,
I am a new member of your group. I have a problem about matrix conversion from Matlab to Maple. In Matlab 7.0 i have created a program,this program sends a result matrix namely AT.This matrix is not symbolic, it is totally numeric. I would like to see this matrix inside of Maple 10. So far i could not make it.
I would be grateful if you could help me.
Greetings.

Hello everyone
I have a question about the use of ExportMatrix and ExportVector. I am currently working on a sheet, where a matrix is changed within a loop. At the end of each cycle of the loop, the eigenvalues of the matrix are calculated and given out in form of a vector.
How can I export these eigenvalue-vectors to a textfile together with the index of the loop?
I already tried to use ExportVector at the end of each cycle, but the command overwrites entries of previous cycles, so that only the very last eigenvalue-vector is noted.
Thank you very much for any help.

Hi,
I want to know if there is a function or simple way that retrieves the constant of an equation?
e.g eq=2x^2+4y-6 the constant here is -6

ex how do i command
# 1 3x+2y+z=2
# 2 4x+2y+2z=8
# 3 x-y+z=4
i can do the math.
(3*#3)+ #1=-5y+2z=10
(4*#3) +#2=6y-2z=-8
add both together y=2
sub in one equation above 6y-2z=-8 z=10
sub into x-y+z=4 x=-4
set this up in maple for me