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06-20-2011
06:03 PM

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06-20-2011
06:03 PM

Adding Matrices & Getting Units Errors

Hi All,

I am trying to add two matrices which have the same units (m^3), but am getting an error. One is a (5x1) and the other a (5x4). I would like to add the column of numbers in the first to each of the columns in the second. Any help would be much appreciated - file attached (page 😎

Thanks

Mark

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06-20-2011
10:53 PM

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06-20-2011
10:53 PM

Mark,

Apparently, unlike M15, you must assign units to 0 as well, at least for a matrix with units.

For tghe if statement with Vshaft.u the 0 must be multiplied by m^3

For the Vshat_l, should do here also, eventhough 0 never came up.

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06-20-2011
10:53 PM

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06-20-2011
10:53 PM

Mark,

Apparently, unlike M15, you must assign units to 0 as well, at least for a matrix with units.

For tghe if statement with Vshaft.u the 0 must be multiplied by m^3

For the Vshat_l, should do here also, eventhough 0 never came up.

06-21-2011
12:03 AM

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06-21-2011
12:03 AM

Mark,

I would delete the units from the inside of the matrix then multiple the matrix by the units. A matrix does not do well with mixed units.

Best of luck

06-21-2011
05:35 AM

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06-21-2011
05:35 AM

The units are not an issue as they are the same. Unfortunatly I do not have access to Prime at the moment, but have Mathcad 15. See if the attached is what your after.

Mike

06-21-2011
05:53 AM

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06-21-2011
05:53 AM

1..Take Wayne's advice with the units! - see attached.

2. You don't always need to use subscripts for every matrix operation - see attached.

3. I suggest you provide different names for each version of your worksheet (at least by adding a, b, c etc or 1, 2, 3 etc.)

Alan

06-21-2011
10:02 AM

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06-21-2011
10:02 AM

2. You don't always need to use subscripts for every matrix operation - see attached.

Alan suggestion above is correct and his example, as mine is worth taking a look at. Using subscripts for every matrix operation is aesthetically unpleasing and hard to follow.

Using alan examples of creating a 1 row, 4 column matrix, see attahced for a little more elegance (in my opinion).

Mike