Mathcad Express Prime 3.0 atan()-function dont work

[ritscheratsche]

Hello friends,
can you give me a Hint how i can get the atan()-funktion work?
Many greetings and thanks in advance,
ritscheratsche

 

[IRstuff]

jeez, where to begin:
> 1st of all, tan()*deg make zero sense, since the result of a tangent operator is dimensionless
> atan(S/100)*deg is likewise a nonsensical construct in Mathcad, since you are effectively saying something like blah*deg^2
> the actual worksheet is ALWAYS more useful than a screenshot of a tiny part of a worksheet
> what little we can see of the sheet implies that you've already defined S to be something, or S is a predefined thing on your sheet. Otherwise, your expressions should return unknowns. In original Mathcad, S is defined to be a siemen, i.e., the inverse of the ohm; nevertheless, Mathcad Prime should likewise return an error
> assuming S is defined to be 17.0224, both expressions would return 0.003 to the precision you show

TTFN (ta ta for now)
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[dik]

I'm not familiar with MathCAD, but I would have thought that atan(S/100) would give an output in rad or degees and you would just have to determine which one you wanted. As IRS notes by using deg, you are forcing an output in deg^2 which may have some sort of output... I dunno.

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-Dik

 

[3DDave]

In general - to diagnose an apparent problem with a function, put in a known constant argument that should return a known result. atan(0) should be 0, atan(1) should be either 45 degrees or the equivalent in radians. Returning a value that is unexpected for an argument that isn't known? Not a good way to start.

 

[dik]

That's the reason for 'back substitution', and yes, using values for which there are known results is good too. If I had have ended up with a different tan value, I'd have been concerned... and I could have just as easily used radian values. I'm pretty confident in SMath unit values.

-----*****-----

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik