Originally Posted by

**Kaitosan** Maybe an example will clarify this up?

"Use a Taylor polynomial to find the S3 approximation of cos 35, and estimate the error in this approximation by using Lagrange's form of the remainder."

After going through the process of setting up the polynomials and numbers, we get.....

cos 35 = sqrt(3)/2 - pi/72 - [sqrt(3)pi^2]/5184 + R

Lagrange's remainder =

R = [sin c (x - pi/6) ]/3!

for some number c between "x" and "a" that maximizes R

Ok, allright?

I actually have two questions. I'd love for someone to clear them up.

1. How is it possible that c=pi/2 if, according to the definition of my book, c is some number between "x" and "a" that maximizes R? By the way, x = pi/6 + pi/36 and a = pi/6.