Adding Matrices & Getting Units Errors

[MarkMcMullan]

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

[wayne · Accepted solution]

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.

[tietjee]

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

[MikeArmstrong]

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

[AlanStevens]

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

[MikeArmstrong]

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