# Polynomial Array formula

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#### NightRider

Does anybody know of an Excel formula for a 4th order polynomial trend? I've been able to write one for a linear trendline but all attemps at a non-linear trendline have failed. I need the formula, not just the graphical representation which I can get in a chart, so that I can analyze the data.
Thanks.

#### Rockn

Look on some search engines. Don't the examples in Excel point in the right direction?

#### NightRider

I've been reading the results from various combos of 'Excel polynomial trendlines formula' searches via Google for the past 4 days and I'm only getting more confused. Excel help does have some formula info, but it is not very specific. Any help would be GREATLY appreciated.

#### Rockn

Don't ask me!! I have problems with monosyllabic speech much less polymorphic polynomial formulas.....LOL. I'll see if I can find aything else.

#### Anne Troy

Anne
Polynomial Array formula

Obviously, you didn't read the part in the agreement about using foul language!

I'm looking too.

#### Anne Troy

Anne
Don't laugh at me if this doesn't help. I found it in "my files".

starting in Row 1, insert the desired polynomial in this format:
=a*(1)^m+b*(1)^(m-1)+j(1) + C
where m is the greatest desired power of x, a,b,j are the corresponding coefficients, and C is the constant in the expression, if any. (1) is a placeholder for the next step, replace (1) with:
(Row()-n)
where n is the value of 1 more than the absolute value biggest negative value in the desired domain (x-values). Copy the formula down n+p rows, where p is the value of the greatest value in your domain and then graph the results.

???

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