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theDeCoder01's avatar
theDeCoder01
Copper Contributor
Mar 16, 2025
Solved

Slope equation calculation (Is it the same as trendline?)

Hi there,   I'm trying to calibrate a temperature monitoring system in reference to a calibrated one. The relation is not linear, so the difference equation is not linear. This is where Excel com...
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excel
Formulas and Functions
  • HansVogelaar's avatar
    HansVogelaar
    Mar 19, 2025

    The forum has been broken since late 2024. I only now got a notification of your reply.

    For a 4th degree polynomial, you can't just calculate the slope - you have to calculate the coefficients for x, x^2, x^3 and x^4. For OpSens CH2 to PICO CH1:

    To use this to predict/interpolate values:

    These values look reasonable to me.

JKPieterse's avatar
JKPieterse
Silver Contributor
Mar 17, 2025

The displayed equation of a trendline may have rounded constants. You can change the number format of the equation by clicking on it and then hitting the short-cut key combination Control+1.

You can then set options like these:

 

theDeCoder01's avatar
theDeCoder01
Copper Contributor
Mar 19, 2025

Hey JKPieterse,

IDK what happened to my first reply to you, but here we go again:

Thank you very much for your input! It did help! Now, the numbers are not random. However, they are still not right.

I'll share a sheet of my workbook with the first graph implementing your idea.

 

Thanks!

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