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Polynomial solving

mehrdad003

New Member
Hi,
I want to find the answer out of this equation (Y) for multiple points (x). I think that excel calculates the formula wrongly.
Appreciate it to guide me. Thanks
Y=60000000000000*x^5+4000000000000*x^4+80000000000*x^3+ 600000000*x^2+ 2000000*x+48.901
 

vletm

Excel Ninja
mehrdad003
Are You sure that You stay within limits with Your formula?
Have You verified limits Calculation specifications and limits
 

vletm

Excel Ninja
mehrdad003
Your I think that excel calculates the formula wrongly.
Have You verified/tested that calculation makes something unwanted?
If Yes ... then which part?
You would have a sample Excel-file, with Your calculations to upload here.

As well as marked - what makes You think something.
 

vletm

Excel Ninja
mehrdad003
My hint - keyword - was a sample Excel-file, which seems missing.
Ps. Why have You used different formula?
eg the last past:
Your original is + 2000000*x+48.901 and
Your snapshot shows + 2000000*x+48.901*x
 

vletm

Excel Ninja
mehrdad003
How those could be the same ... if those are different formulas?
You chart seems to linked ... someway.
Why Your cell D40
You given data is not sorted, after sorting 'chart' looks smoother.
Did You do If Yes ... then which part?
... seems not, I did
Do right side file give better values?
... but are those correct?
 

Attachments

p45cal

Well-Known Member
The problem arises from your taking the coefficients from the chart display of the coefficients.
Two things you can do:
1. Configure the chart to show the coefficients to more decimal places:
74687

2. Use LINEST to get your coefficients:
74688
(You didn't supply the source data in your file so I extracted it from the chart into the same sheet - you won't need to do that)
There must be a slightly different way Excel calculates the coefficients on the chart compared to the formula on the sheet, so take your choice where you take the actual values from.
since according to the graph, Y should be around 50 not 84.8
Here are the results from the LINEST coefficients:
74689
 

mehrdad003

New Member
mehrdad003
How those could be the same ... if those are different formulas?
You chart seems to linked ... someway.
Why Your cell D40
You given data is not sorted, after sorting 'chart' looks smoother.
Did You do If Yes ... then which part?
... seems not, I did
Do right side file give better values?
... but are those correct?
Hi, Thanks but I am not allowed to sort the data since they are extracted from experiment.
 

vletm

Excel Ninja
mehrdad003
Sort was to get better look with Your give data.
I was more worry about Your given formulas
... which seems to be something like misinformation.
My right side file cannot be correct ... but it would look better.
Maybe next time.
 
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