Zero of a Polynom and of a function

[Albert Chan]

(11-22-2021 02:37 PM)Gil Wrote:  Let's put the array [an... a0] in the order, as requested:
[ 2.231958E-9 5.31165E-10 3.789584E-9 8.003727E-7 .000000131844 -.00006116623 ]

Based on your posted f, you missed negative sign for df/dt linear term.

A trick to avoid typo mistake is to wrrite equation with sign "stick" to the number, like this:
At a glance, we know df/dt has 2 negative terms.

f=
+0.2421904482
−0.00006116623*t
−0.000000065922*t^2
+2.667909E-7*t^3
+9.47396E-10*t^4
+1.06233E-10*t^5
+3.71993E-10*t^6,

with t= (Julian Day - 2451545)/365250.

Also, min(t) = 6.51025795855 is likely meaningless.
I seriously doubt the equation can predict this far out , year 2000+6510 = 8510 !

It may be just an artifact to curve fit available data to polynomial.