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Thread Subject:
Matlab 2009A issues...HELP

Subject: Matlab 2009A issues...HELP

From: Ryan

Date: 28 Oct, 2009 21:35:08

Message: 1 of 2

Hello,
We are having an issue running Matlab 2009A in our labs.

I know nothing about matlab I am the lab admin so bare with me.

The following issues occur:

First when trying to enter the commands
syms x
y=tan(x)*sin(x);
yi=int(y);

after the yi= line I get an error message stating
WARNING: explicit integral could not be found. In sym int at 64


After some research I found that this may be an error with the MUPAD engine in matlab. So I tried using the symengine command to change to the maple engine. We have the full version of Maple 12 installed on the computers. I tried to point as requested by matlab to the maple location but get an error saying "the directory does not contain a version compatable with symbolic math toolbox gateway."

I have 500+ machines with matlab on it so updating to the new 2009b is not an option.

Ideas please????????

Subject: Matlab 2009A issues...HELP

From: Steven Lord

Date: 30 Oct, 2009 14:47:51

Message: 2 of 2


"Ryan " <none@none.com> wrote in message
news:hcadec$do$1@fred.mathworks.com...
> Hello,
> We are having an issue running Matlab 2009A in our labs.
>
> I know nothing about matlab I am the lab admin so bare with me.
>
> The following issues occur:
>
> First when trying to enter the commands
> syms x
> y=tan(x)*sin(x);
> yi=int(y);
>
> after the yi= line I get an error message stating
> WARNING: explicit integral could not be found. In sym int at 64

This is NOT, repeat NOT an error message; as the first word of the message
indicates, the symbolic INT function is warning you that it doesn't know an
explicit form for the integral of the symbolic expression you gave it. In
this case, though, you can modify the form of the expression slightly to get
it into a form INT knows how to handle.

>> syms x
y = sin(x)*sin(x)/cos(x); % using the definition of tan(x)
yi = int(y)

yi =

log(tan(pi/4 + x/2)) - sin(x)

I've checked this result against a table of integrals on my bookshelf [which
did not contain the form sin(x)*tan(x) but instead contained
sin(x)^2/cos(x)] and it agrees with the table.

> After some research I found that this may be an error with the MUPAD
> engine in matlab.

Possibly, but I think it's more likely that the symbolic engine didn't
recognize the integral in its table and didn't realize how to apply its
simplification rules to get it into a form that it recognized.

> So I tried using the symengine command to change to the maple engine. We
> have the full version of Maple 12 installed on the computers. I tried to
> point as requested by matlab to the maple location but get an error saying
> "the directory does not contain a version compatable with symbolic math
> toolbox gateway."

Do you have the correct version of the Maple Toolbox?

http://www.mathworks.com/support/solutions/en/data/1-8IONJU/?solution=1-8IONJU

If that doesn't work, you should work with Technical Support to determine
why SYMENGINE didn't work and how to make it work.

--
Steve Lord
slord@mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ

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