Polynomial curve fitting with EXCELL
Polynomial curve fitting with EXCELL
(OP)
Hi,
With 2 columns (X and Y) of data, I got from Excell 2003 the curve and the following equation : y = 23E-04X3 + 4E-05X2 - 3E-06X + 0,007
What E means ? Is it Sigma symbol?
I am not familiar with this application.
How can I use this formula to get Y values from any X input ?
Thanks
With 2 columns (X and Y) of data, I got from Excell 2003 the curve and the following equation : y = 23E-04X3 + 4E-05X2 - 3E-06X + 0,007
What E means ? Is it Sigma symbol?
I am not familiar with this application.
How can I use this formula to get Y values from any X input ?
Thanks





RE: Polynomial curve fitting with EXCELL
So 23E-04 is 23 x 10^-4 or 0.0023.
RE: Polynomial curve fitting with EXCELL
Hi,
From the two columns of data below, I got the formula: 6E-09X^3-3E-05X^2+0,0165X+6,3375 with R^2=1
However, when I enter one value coming from the data, let's say 1071, I get the wrong number of -3,03
It should be 2. Please, let me know how to match correctly the best fit curve.
CFM Static pressure Performance from fan curve:
(in) Cfm Static pressure
1127 1 1071 -3,03
1071 2
1014 3
953 4
888 5
817 6
736 7
638 8
RE: Polynomial curve fitting with EXCELL
Why do you think that a single digit of precision is adequate for this task? Is this a homework assignment?
TTFN

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RE: Polynomial curve fitting with EXCELL
I got this equation from Excel's polynomial trendline.
I have no idea how to get more digit,...
These data are from a fan performance table. We try to get the equation of this fan curve
to be able to have performance at any point on the curve.
Must know how to get more digit,...
RE: Polynomial curve fitting with EXCELL
TTFN

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RE: Polynomial curve fitting with EXCELL
It means that the equation describes the mathematical function that best describes ALL of the points.
RE: Polynomial curve fitting with EXCELL
TTFN

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Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: Polynomial curve fitting with EXCELL
polynomial equation,...
Excel give me only one digit,...
RE: Polynomial curve fitting with EXCELL
> Select Format Trendline Label ( 3rd from bottom
> Select Number | Scientific | 4 digits
TTFN

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RE: Polynomial curve fitting with EXCELL
It's been discussed here in the spreadsheet forum many times. Search works.
RE: Polynomial curve fitting with EXCELL