Hi, ask a question about the unit in Mathcad

junzai-disabled · ‎Sep 23, 2009

How can I chance the unit such as from "kg/m" to "lb/in"?

I want to calculate the value of matrix /A/, but the computer tells me that it can not calculate the value with a unit, so what should I do?

PhilipOakley · ‎Sep 23, 2009

An example worksheet would be useful. You may have confounded two problems.

1. if you type A = you should see a small black box at the right hand side. When you click on that you can enter any multipler, especially the units of your choice.

2. if yuou were asking for |A| (determinant) of a matix wher each value has (the same) units then you have probably misunderstood what you asked for. the determinant multipliers all the elements to gether in that clever way, but in doing so would also multiplies the units together, which is not usually wanted. MathCAD say's No.

3. If you wanted the absolute of each element, you need to select the absolute from the calculator pallete, then appliy the vectorise operator (the over-bar arrow) on the matrix pallete (rather than the similar looking || determinant operator on the matrix palette)

Philip Oakley

IRstuff · ‎Sep 23, 2009

On 9/23/2009 3:45:53 PM, junzai wrote:
>How can I chance the unit such
>as from "kg/m" to "lb/in"?
>
>I want to calculate the value
>of matrix /A/, but the
>computer tells me that it can
>not calculate the value with a
>unit, so what should I do?

You have units attached to |A|? Then, you might need to remove the units, no?

TTFN,
Eden

ptc-1368288 · ‎Sep 23, 2009

On 9/23/2009 3:45:53 PM, junzai wrote:
>How can I chance the unit such
>as from "kg/m" to "lb/in"?

==> define your own unit
==> kgm:=1
==> kgm = "kg/m"
==> make sure your Engineering formula is built around "kg/m" !!!

>I want to calculate the value
>of matrix /A/, but the
>computer tells me that it can
>not calculate the value with a
>unit, so what should I do ?

==> once you have introduced units & carried respectfully the "UserUnitResult" is unique and it should tabulate. If it does not tabulate, you have a coherence problem in the formula.

jmG