18 years, 5 days

## Using Matrix Equations...

Thank you for making me aware of GenerateEquations. After examining this procedure I have decided to use my own methods which, if anyone is interested, are described in the uploaded file. Download 2292_MatrixEquation2.mw
View file details

## Waltzing with MAPLE...

Thank you. I'm learning useful stuff here all the time. Now I know about appending ",details" to a help query to get more info. When I query ?dsolve,details I see various forms of the dsolve() command. The presentation does seem to imply that if one uses an IC one must include as a second parameter the function to be solved for. The help file accessed by ?dsolve,details shows this dsolve({ODE, ICs}, y(x), extra_args) but not this dsolve({ODE, ICs}) But the latter form does work *sometimes*, and in fact is in one of the examples given when one queries ?dsolve. Rather than spending alot of time trying to figure out why that form works sometimes and not other times I'll just include the second paramater when I am using IC's. I'm becoming more and more aware of the fact that one must learn to waltz with MAPLE. Thanks again.

## Solving DE's...

Thank you. That works. From the examples given when one types ?dsolve I would not have figured out to do it that way. The help file shows examples of solving a de with initial conditions without using 2 arguments to dsolve(). In fact, the help file doesn't give any clear idea of when a second parameter (which defines the function to be solved for) is needed in dsolve. I guess that's another example of MAPLE quirkiness. The following works: ode := diff(y(x),x,x) = 2*y(x) + 1; ics := y(0)=1, D(y)(0)=0; dsolve({ode,ics}); Go figure :)

## Cross Product...

Thank you J. I am familiar with CrossProduct in the linear algebra package. That function produces a sum of 3 products each of which is a product containing the unit vector in the x, y and z direction respectively. For some purposes this is useful, but not for what I am trying to do. The routine I wrote produces a vector of 3 components, which is what I want. What I was hoping was that I could get the same result by using some operator symbol between the 2 vectors. I was able to define &X so that it accomplished this. I found out later by playing around that the bold dot symbol in the MAPLE list of operator symbols does in fact produce the dot product of 2 vectors. This has the advantage that you don't need to use '&' and you don't need space around the operator. The cross symbol in that list does not, however, produce the cross product. I was wondering if there is any way in MAPLE to write something like AxB and have it produce a vector which is the cross product of A and B. I already know, as my file shows, how to define &X in such a way as to obtain the cross product by writing A &X B but I would prefer a less cumbersome representation and was wondering if this is possible in MAPLE. The fact that the bold dot in the operators list produced the dot product was encouraging. There's quite a few wierd symbols in that list. I suppose I could try all of them. The one which is an x inside a circle doesn't appear to work. Anyway, thanks for your input.

Hi Will. The post I am referring to is the only post by GeorgeJ in the MAPLE T.A. forum. If you have time to respond to this post, could you walk me through how one includes in one's post a hyperlink to another specific post? Thank you

## Thank you...

Thank you Alex. You've been very helpful, here and in the other thread. I notice one curious thing. I have 80 posts, so I get a silver leaf. Yipee! Fact is, my posts have all been fairly basic questions so anyone inferring competence based on the color of my leaf would be making a mistake. I haven't helped anyone yet. I hope someday I will be able to. On the other hand you, who have only posted 15 times, obviously know much much more about MAPLE than I do. I sure wouldn't know nearly as much about MAPLE as I do now if I had only posted 15 times. Without MAPLEPRIMES I would be lost.

## This is weird...

Alex, this gets "curiouser and curiouser". I just copied your proc1 code into a MAPLE 10 worksheet and it generated an "unable to parse" error. When I changed the first two colons to semi-colons it worked fine. If it really did parse the way you wrote it, then I would be curious to know what version of MAPLE you are using. Could there be some global setting having to do with colons and semi-colons? I'm not going to spend alot of time on this becasue its no big deal to replace colons with semi-colons, but it is curious that this seems to be necessary for me and not for you. Thank you for your post.

## Self response...

O.K. I just figured it out. For some reason that is inexplicable (to me) one must use the semi-colon rather than the colon when seperating the declaration of local and global variables. So this parses proc1 := proc () local i, j; global k; end proc and this doesen't proc1:=proc() local i,j: global k: end proc I had thought the two symbols were interchangable within a procedure and as a habit always used the colon. I guess I'll switch to always using the semi-colon, except maybe after the last statement, depending on whether or not I want the code outputed. Its curious that the first time a problem occured was when I was trying to define both global and local variables within a procedure. Before that the colon worked fine as a statement terminator. Oh well....

## More Problems...

Thanks J. I'm trying to see if there is any way, just using the MAPLE collect, subs, and simplify commands, to get from the output of 4*int(sqrt(r^2-y^2),y=0..r-z) assuming r>z,r>0; to this 2*sqrt(z*((2*r) - z))*(r-z) - 2*r^2*arcsin((-r+z)/r); which is a simplification of the output of the first line. I like just using these commands rather than manipulating manually in order to minimize the possiblility of error.

## Doesn't seem to work...

This is what happens

>

>

Error, invalid arrow procedure

>

This post was generated using the MaplePrimes File Manager

View file details

View file details

## Bug in MAPLE discovered?...

Thank you Georgios. I was unaware of the feature you showed me. In some circumstances the workaround which you showed me can be used. However, I am still very confused as to why the problem occurs. I have created and uploaded another worksheet which zeroes in on the problem. I would be very interersted in having someone tell me why the problem occurs. Have I discovered a bug in MAPLE? View 2292_WhatsGoingOnHere.mw on MapleNet or Download 2292_WhatsGoingOnHere.mw
View file details

## Page Numbers Not Printing...

Will, I'm enclosing a file which has nothing but garbage in it. It was specifically created so that a printout would include at least 3 pages. Page Numbers are enabled in the manner I mention in my prevous post. When I do a print/preview I see the page numbers at the bottom of each page, but when I actually print out the file either to our office Konica 7135 or to a PDF file using Adobe Acrobat, the page number only appears on the first page. Becuse I get this result with 2 distinct printer drivers it seems unlikely that a printer driver is at fault. I am now using the lastest update of MAPLE 10 10.06, OCt 2 2006. View 2292_Garbage.mw on MapleNet or Download 2292_Garbage.mw
View file details

## Page Numbers...

Click Format/Page Numbers A window will appear. In the window is, among other things, a check box which has the accompanying text "enable page numbers". I click in that box. Then when I Print/preview my worksheet I see page numbers at the bottom of every page, but when I go to print the file I only get a page number on the first page.

## Her'es the Sudoku program...

Well, I don't have a blog yet. I may set one up some time. Really hadn't thought about it. In the mean time, if anyone is interested in the Sudoku program in Excel, here it is. If excel files are deemed inappropriate on this forum I will certainly respect that in future if I am so informed. Download 2292_Sudoku18.xls
View file details
 1 2 3 4 5 Page 4 of 5
﻿