Asked by:
Thanks

## question about fractional form / evaluating cfrac ...

Asked by:
Where can I find a description for the various variants of numtheory:-cfrac, which goes more into details than the online help? For example one can guess how an approximating sum can be obtained from numtheory:-cfrac((a+x)^k, x, 7, 'diag', 'simregular', 'quotients'); but I prefer to cross-check against a confirmed formula instead of guessing. If somebody would be so kind to point me to some source to look at ... or even knows it already ...: how does one evaluate the above list to get a value? -- edited to add: I mean a way which can be compiled and without running through

## Please help me on solving Navier Stokes equations....

Asked by:
3 equations are: diff(u_r(r,theta),r)+2/r*u_r(r,theta)+1/r*diff(u_theta(r,theta),theta)+cos(theta)/sin(theta)/r*u_theta(r,theta)=0; -diff(p(r,theta),r)+mu*(diff(u_r(r,theta),r,r)+2/r*diff(u_r(r,theta),r)-2/r^2*u_r(r,theta)+1/r^2*diff(u_r(r,theta),theta,theta)+cos(theta)/sin(theta)/r^2*diff(u_r(r,theta),theta)-2/r^2*diff(u_theta(r,theta),theta)-2*cos(theta)/sin(theta)/r^2*u_theta(r,theta))=0; -1/r*diff(p(r,theta),theta)+mu*(diff(u_theta(r,theta),r,r)+2/r*diff(u_theta(r,theta),r)-1/(r^2*sin(theta)^2)*u_theta(r,theta)+1/r^2*diff(u_theta(r,theta),theta,theta)+cos(theta)/sin(theta)/r^2*diff(u_theta(r,theta),theta)+2/r^2*diff(u_r(r,theta),theta))=0;

## Is this a bug in Matlab code generation?...

Asked by:
Seems that Maple outputs ".." instead of ":" for Matlab code. Note that I'm using Matlab 6.5, so not sure if version has anything to do with it. Is this a bug? Any help would be greatly appreciated. Thanks. >Matlab Code generated from Maple follows

## Having problem with infinite series...

Asked by:
I tried Maple to find a closed-form expression of the following infinite
series:
F:=sum(r^j/(1-a*z^j),j=1..infinity)
where r and a are probabilities and |z|<1.
It did not work
Then I tried to get a series expansion of F around z=0, i.e:
G:=series(F,z=0);
Got the following error message:
Error, (in series/exp) unable to compute series
However when the upper limit of the summation is changed from infinity to any pre-defined number;
ex: F:=sum(r^j/(1-a*z^j),j=1..100)
Maple was able to derive the series expansion around z=0.
Is there any way to get the series expansion at z=0, when the upper limit of the summation is infinity ?

## system of ode of predator prey models...

Asked by:
hi, i don't know maple at all and i need to figure out how to solve this sytem of equations that model predator prey systems in maple but i get an error when i modify this code > e1 := diff(x(t),t) = k*x(t) - a*x(t)*y(t); > e2 := diff(y(t),t) = -r*y(t) + b*x(t)*y(t); to fit this equation- dx/dt = 2x(1-x/4) - xy dy/dt = -3y + xy x(0) = 1 y(0) = 1 if anyone has time to tell me what i can do to get the equilibrium points, the solution and the table of values for this system, i would be grateful

## Appell Hypergeometric Function F2...

Asked by:
Hi, How can i compute the F2 Appell Hypergeometric Function using Maple? Can i write F2 as a function of the F1 appell function? Thank you. Appell Functions: http://mathworld.wolfram.com/AppellHypergeometricFunction.html

## importing data and manipulating it...

Asked by:
ok, my first question, and as I only started using maple about 1hr ago, its probably rather a simple solution that I've missed. I'll tell you what i'm trying to do, and what I've tried so far. I've run some code which has given a formatted output of a lot of numerical data, in 4 columns (which I may wish to call x,y,T and P if I can). I wish to import this data into maple, so that I can eventually plot contour plots with it of T on a x and y grid, and P on an x and y grid. Having tried to use the readdata command to read the file in, I got a lot of row vectors. However I then couldn't find out how to reference specific values in these vectors to allow me to assign them to variable values, or maybe just directly plot them. I tried using the importmatrix command to see if that gave anything, but that failed entirely.

## Few questions about Maplet....

Asked by:
I currently have some MathMLViewers in my maplet and I don't want them to have vertical scroll bar at all times. Does anyone know how to switch vertical scroll bar off for MathMLViewer? Also, is any way that I can have two windows dispaly at same time so I can change window focus by clicking window? Last question, is it possible to display multiple items in ListBox by using Set("ListBox_Name"('value') = blah, blah, blah); Looking forward for your respond, thank you. Tracy

## Restrictions of parameters fit ??...

Asked by:
Hi, I have a problem with fit parameters restrictions. I would like to give restrictions of the parameters of my fit in order to get the best fit parameters, but the "parameterranges" seems to be not in function. my function is following: > y1 := piecewise(0 <><>

## Open Maple, arrays and memory copy...

Asked by:
I have the following: arrays arrC of type double in a C code and a fct in Maple allowing arrM of type Array(datatype = float[8]) as argument. I want to evaluate the fct using arrC as input. For that one can either use 'MapleAssignIndexed' (looping through the elements if there are not very much of them), or 'RTableCreate' (details omitted). Both seem to need some overhead which costs time. Is there a way to use something like the C function memcpy to copy the array to Maple (assuming the correct space can be supplied) to speed it up? Does one have to work with byte arrays instead for that - or is it

## protect table...

Asked by:
Hello, I was wondering whether there is any way to protect a table. I have the following situation: > f := table([ a = table([ a1 = 1, a2 = 2 ]), b = table([ b1 = 3, b2 = 4 ]) ]); That is, f[a] returns another indexed table. Now, when I do protect(f), protect(f[a]) or even protect(f[a][a1]), I cannot change its value any more: > protect(f); > f[a][a1] := test; Error, attempting to assign to array/table `f` which is protected But if I assign f[a] to a new variable g, then I can do it: > g := f[a]; > g[a1] := test; > eval(f); table([a = table([a1 = test, a2 = c]), d = table([d1 = i, d2 = j])])

## discont function...

Asked by:
I noticed that this function is used only for a discontinous function. What can I do if I have a discontinous data?

## problem with fsolve...

Asked by:
I'm trying to generate a list of solutions by changing two parameters as follows (T,x[1,a]): A:=0.2:Q:=273.15: > J:=10: > K:=283.15: > U:=0.4: > V:=0.1: > W:=0.8: > N:=(K-Q)/J+1: > M:=(W-U)/V+1: > data:=[]: > List:=[]: > forget(fsolve); > for T from Q by J to K do > eq[1]:=x[1,a]*alpha[1,a]=x[1,b]*alpha[1,b]: > eq[2]:=x[2,a]*alpha[2,a]=x[2,b]*alpha[2,b]:

## From Matrix DE solution to Equation form...

Asked by:
Hey all I would like to know if after solving a Matrix Differntial Equation (general form, no initial conditions) there is a way to convert the solution matrix to equation form (i.e. y(t)= C_1e^(3t)+C_2e^(-t)+... etc). see yas david
 First 326 327 328 329 330 331 Page 328 of 331
﻿