drawing a curve and find the formula 2

• Mar 8, 2023

• #2

CarlB

Civil/Environmental

Jul 11, 2001

1,178

Yes, in Excel.

https://mathstat.slu.edu/~may/ExcelCalculus/sec-1-5-IntroBestFitCurves.html

 

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• Mar 9, 2023

• Thread starter
• #3

robyengIT

Mechanical

Dec 20, 2013

894

Thanks. I knew this solution and I did. Now I will check whith some of the instructions I didn't know. Thks again

 

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• Mar 9, 2023

• #4

fel3

Civil/Environmental

Jul 9, 2001

882

If you need more curve fitting options than Excel provides, you can try CurveExpert Basic or CurveExpert Pro:

https://www.curveexpert.net/

============
"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

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• Mar 10, 2023

• #5

dik

Structural

Apr 13, 2001

25,752

If you can make heads or tails of it... old basic library file attached.

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/raw/upload/v1678427617/tips/FITCURVE_par2uk.BAS[/url]

There was an HP publication on curve fitting... I'll see if I can dig it up... I may have the original, and I know I scanned it... It had numerous approaches to curve fitting for various types of curves and various types of data.

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

-Dik

 

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• Mar 10, 2023

1
• #6

dik

Structural

Apr 13, 2001

25,752

these were the curve functions...

Stuff I did 30 years ago... used BASIC in lieu of C... the Microsoft Basic math library used the Fortran library and was faster than the C library. With 8088 processors, it mattered back then...

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

-Dik

 

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• Mar 10, 2023

1
• Thread starter
• #7

robyengIT

Mechanical

Dec 20, 2013

894

Fel3 : I bought the pro version. Absolutely fine. THANKS

 

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• Mar 20, 2023

• #8

IDS

Civil/Environmental

Jun 1, 2001

3,208

Several articles on curve-fitting with Excel here:

https://newtonexcelbach.com/?s=fit+polynomial

Including buit-in functions, Alglib, and Python functions.



Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/

 

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• Apr 9, 2023

• #9

IanVG

Mechanical

Jan 21, 2022

74

Free and basic version available online is WebPlotDigitizer; I'm using it to recreate pump curves from old printouts. Link here.

 

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