After changing the variables to X i = x i, the calculations are completely similar to the linear case y = a n*X n +. + a 3*x 3 + a 2*x 2 + a 1*x + b is transformed to a linear function using a change of variables. Note: Excel uses a linear model: the polynomial function y = a n*x n + . Excel works with polynomial orders from 2 nd to 6 th.

n is the degree of the polynomial (in Excel, the order of a polynomial).

, a 3, a 2, a 1 and b are calculated parameters of the function (also named function coefficients or constants) that describe the relationship between x and y, The polynomial trendline is a curved line with the function:

Polynomial trendline equation and formulas

a dependent or response variable y (named as known_y's).

an independent, predictor, or explanatory variable x (named as known_x's),.

If const is FALSE, the parameter a is set to 1.The degree of the polynomial is specified in the Order field - see more about the polynomial trendline in Excel.Įxcel uses the least squares method to fit a polyline for the data points.įor a trend line, two sets of variables are required:.

If const is TRUE or omitted, the parameter a is calculated normally,.

const (optional) is a Boolean value specifying whether to force the parameter a to equal 1:.

If you omit new_x's, it is assumed to be the same as known_x's,.

new_x's (optional) are the new x-values for which the GROWTH () function should calculate corresponding y-values:.

In any case, you should provide the known_x's or array that has the same size as known_y's, These variables cannot be omitted for the correct calculation of a power trend. known_x's (optional) are independent data values:.

known_y's (required) are dependent data values,.

The array function LOGEST () calculates the power curve that fits best the known data and then returns an array with statistics describing the trend line: The array function LINEST () calculates the linear trend that fits best the known data and then returns an array with statistics describing the trend line:

number (required) is a number to take the natural logarithm of.

The LN () function is the inverse of the EXP () function and returns the natural logarithm of a given number:

number (required) is a power that e is raised to.

The EXP () function returns the result of the constant e raised to the power of a number:

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