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Mathcad prime 4.0 issue with °F units

AL_9913769
Regular Member

Mathcad prime 4.0 issue with °F units

I'm subtracting 2 temperatures. But Mathcad gives an unexpected answer:

AL_9913769_1-1621269790902.png

ΔT should equal 280°F.

 

4 REPLIES 4

Re: Mathcad prime 4.0 issue with °F units

There are two types of temperature units in Prime, absolute and relative. You're using the absolute Fahrenheit units. This means that every temperature is converted to absolute temperature in kelvin, then subtracted, then the result is converted back to Fahrenheit because you requested the result to be Fahrenheit.

You should use Delta°F instead of °F for the result. See ttokoro's examples below.

 

Success!
Luc

Re: Mathcad prime 4.0 issue with °F units

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Re: Mathcad prime 4.0 issue with °F units


@PrepaidGiftBalance wrote:

I'm subtracting 2 temperatures. But Mathcad gives an unexpected answer:

AL_9913769_1-1621269790902.png

ΔT should equal 280°F.

 


Using MathCad 15 and older, type the units you want to report in the black highlighted box next to the executed calculation. The units and reported answer will auto-update. With MathCad Prime, you need to manually delete each character of the reported base units, then type your preferred unit of measure...it will then update when you hit 'enter'.

I'm not certain, but I've always seen MathCad report base units and the user had to correct this for each desired calculation.

Re: Mathcad prime 4.0 issue with °F units


@AL_9913769 wrote:

I'm subtracting 2 temperatures. But Mathcad gives an unexpected answer:

AL_9913769_1-1621269790902.png

ΔT should equal 280°F.

 


The 350°F are an absolute temp, but the 70°F are a relative temp.

 So IMHO the appropriate approach would be

Werner_E_0-1621636094411.png

 

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