Lagrangian Interpolation

[Thomas Klemm]

(03-14-2019 07:22 PM)PedroLeiva Wrote:  so we cannot use it for 3rd. or 4th. order, considering we will need 4 or 5 points. Am I right?

Correct.
In this case you could use (42S) Newton Polynomial Interpolation.
It allows to enter as many points as you like and memory allows.
Given the restrictions of the HP-25 I'm afraid we can't go further than 3 points.

Cheers
Thomas