cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Showing results for 
Search instead for 
Did you mean: 

Community Tip - You can change your system assigned username to something more personal in your community settings. X

I need the right units

ppal
17-Peridot

I need the right units

How can I get A rather than V/ Ω

 

ppal_0-1662412897659.png

Thanks

 

1 ACCEPTED SOLUTION

Accepted Solutions

Hi,

Prime symbolic engine treats units as variables.

Use numeric engine for units

Capture.JPG 

View solution in original post

3 REPLIES 3

Hi,

Prime symbolic engine treats units as variables.

Use numeric engine for units

Capture.JPG 

Werner_E
24-Ruby V
(To:ppal)

Terry workaround using the numerics and a finite sum up to 5000 should be quite sufficient for most applications, I guess. So I consider it the best solution and the preferred way to go, avoiding the symbolic evaluation completely.

 

Just for fun here some other ways to get the final unit. But let me first say that if you use units in conjunction with symbolic evaluations, you should turn on this option:

Werner_E_0-1662419383394.png

It doesn't help a lot but at least a little bit. You can tell from the color that now V, etc. in the output of the symbolic evaluation are seen as units.

Nonetheless the symbolics still does not know that volt/ohm=ampere.

If you like, you can instruct the symbolics about this connection (but I would consider it too much of a hassle)

Werner_E_1-1662419585251.png

If you want to use the "exact" symbolic evaluation because you want use the infinite sum, you can either follow the symbolic evaluation by a numeric one

Werner_E_2-1662419653870.png

or you may assign the result to a variable and evaluate that variable in an extra region (would be my preferred way to do it).

Werner_E_3-1662419719928.png

 

In case you are wondering why the "exact" symbolic just gives you with 264.0 a numeric float result instead of the pure 264 (=240*11/10). This is because you use a float number (1.1) in your expression. As soon as you do so, the symbolic engine switches into some kind of numeric float mode (similar to what you get when you use the modifier "float").
There is no way to change this other than avoiding float numbers:

Werner_E_4-1662420162337.pngor  Werner_E_5-1662420178272.png

 

 

LucMeekes
23-Emerald III
(To:ppal)

If you want an exact result, use the symbolics properly:

LucMeekes_0-1662455650707.png

So this complicated sum to infinity reduces to a simple quotient.

 

Success!
Luc

Top Tags