Wrong unit for (variable with units)^number

Wrong unit for (variable with units)^number - Messages

#1 Posted: 5/20/2023 2:50:55 AM
JP

JP

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I have:

x=number (inches)

A=x^-number

A= decimal number.fraction (unit)

Why am I getting a results that is a product of decimal and fraction rather than a decimal or fraction?

The unit seems to be only for the fraction.

I am not sure how to paste my results from SMath Studio.
#2 Posted: 5/20/2023 3:06:10 AM
Valery Ochkov

Valery Ochkov

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Wrote

I have:

x=number (inches)

A=x^-number

A= decimal number.fraction (unit)

Why am I getting a results that is a product of decimal and fraction rather than a decimal or fraction?

The unit seems to be only for the fraction.

I am not sure how to paste my results from SMath Studio.


in.png
#3 Posted: 5/20/2023 4:11:14 AM
Alvaro Diaz Falconi

Alvaro Diaz Falconi

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Wrote

I have:

x=number (inches)
A=x^-number
A= decimal number. Fraction (unit)

Why am I getting a results that is a product of decimal and fraction rather than a decimal or fraction? ...



Because that's the correct answer:

Clipboard01.png

Wrote

... The unit seems to be only for the fraction. ...



Powering units could be some confuse, but don't worry, more confusing could be check the SI official standard about how to write it.

Best regards.
Alvaro.
#4 Posted: 5/20/2023 10:01:30 AM
JP

JP

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Group: User

How do I ignore the units for x=7 in when used in the A=x^2 formula?

I tried 'ignore units' and it did not change anything.

Thanks!
#5 Posted: 5/20/2023 12:20:31 PM
Jean Giraud

Jean Giraud

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Wrote

How do I ignore the units for x:=7


Type 7 ... multiply ... type ' [apostrophe]
In the round place holder ... Units inch

SilentUnit.PNG
#6 Posted: 5/20/2023 2:26:15 PM
Jean Giraud

Jean Giraud

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Wrote

Originally Posted by: Jean Giraud [url=/forum/yaf_postsm81315_Wrong-unit-for--variable-with-units-number.aspx#post81315][/url]Type 7 ... multiply ... type ' [apostrophe]
In the round place holder ... Units inch


Does it work as you demanded ?
#7 Posted: 5/20/2023 3:02:47 PM
overlord

overlord

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.
Wrote

Type 7 ... multiply ... type ' [apostrophe]
In the round place holder ... Units inch


Never do this, Razonar's approach is the correct one.
Jean is simply against SI units, don't listen to him for anything involved units.

And never ever use Jean's engineering calculations for anything.
They are notorious for being wrong and giving false results.

If he insists at anytime about using SMath 0.99.6179, simply ignore it.
That is a 6+ year old version of SMath, always use latest stable.

Regards
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Alvaro Diaz Falconi 5/20/2023 6:34:00 PM
#8 Posted: 5/20/2023 6:27:54 PM
Alvaro Diaz Falconi

Alvaro Diaz Falconi

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Wrote

How do I ignore the units for x=7 in when used in the A=x^2 formula? ...



Hi. Something like this?

Clipboard01.png

Best regards.
Alvaro.

#9 Posted: 5/21/2023 5:32:01 PM
JP

JP

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@Razonar

Not sure. If I use 'A' in another equation, will it consider the units for A?

I dont what it to as it will mess up the units for that answer...which will mess up the units for the subsequent equation.
#10 Posted: 5/21/2023 7:12:35 PM
Alvaro Diaz Falconi

Alvaro Diaz Falconi

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The choice as to whether you want to use A with or without units is yours. You can use the version of A with units, or the version of A without units. But not both at the same time.

Best regards.
Alvaro.
#11 Posted: 5/22/2023 6:49:46 AM
Martin Kraska

Martin Kraska

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Wrote

I have:

x=number (inches)

A=x^-number

A= decimal number.fraction (unit)

Why am I getting a results that is a product of decimal and fraction rather than a decimal or fraction?

The unit seems to be only for the fraction.

I am not sure how to paste my results from SMath Studio.



Such problems usually emerge if you have an equation where the variables aren't meant to be numerical values of quantities given in a particular unit rather than being real physical quantities (number times unit).

SMath is designed for work with quantity times unit variables. If you want to use an empirical equation, you also must provide the units of each variable (be it input or result).

You can integrate such equations into a world of proper handling of physical quantites by dividing each input parameter by the unit in which it is supposed to be inserted and by multiplying the expression by the unit in which the result is supposed to be given by that empirical model.

Worksheet2.png
Worksheet2.sm (5 KiB) downloaded 27 time(s).
Martin Kraska Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx
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Alvaro Diaz Falconi 5/22/2023 11:36:00 AM
#12 Posted: 5/22/2023 11:35:24 AM
Alvaro Diaz Falconi

Alvaro Diaz Falconi

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Wrote

... You can integrate such equations into a world of proper handling of physical quantites by dividing each input parameter by the unit in which it is supposed to be inserted and by multiplying the expression by the unit in which the result is supposed to be given by that empirical model.



That is a very smart recommendation.

Best regards.
Alvaro.

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