Numerical Analysis/Lagrange example

We'll find the interpolating polynomial passing through the points , , , using the Lagrange method.

We first use the formula to write the following:

After some simplification, we get:

And our answer:


Adding a point edit

Now we'll add a point to our data set, and find a new interpolating polynomial. Let us add the point   to our set. Starting over with the Lagrange formula, we write:


Simplifying, we get:



And our polynomial is: