GROWTH(known_ys,known_xs,new_xs,affine)
known_ys: known y-values
known_xs: known x-values; defaults to the array {1, 2, 3, …}
new_xs: x-values for which to estimate the y-values; defaults to known_xs
affine: if true, the model contains a constant term, defaults to true
GROWTH function applies the “least squares” method to fit an exponential curve to your data and predicts the exponential growth by using this curve.
GROWTH returns an array having one column and a row for each data point in new_xs.
If known_ys and known_xs have unequal number of data points, this function returns a #NUM! error.