# Math Help - Taylor approximation of cos

1. ## Taylor approximation of cos

Calculate cos(.1) to seven decimal places.

2. Originally Posted by cgiulz
Calculate cos(.1) to seven decimal places.
What are you having trouble with? Figuring out the series or how to get 7 decimal places?

3. Here is where I am:

Since $R_{5} (.1) = |-\cos(c)| \frac{.1^{12}}{12!} \leq \frac{.1^{12}}{12!} < ...$

$\cos(.1) = 1 - \frac{.1^2}{2!} + \frac{.1^4}{4!} - \frac{.1^6}{6!} + \frac{.1^8}{8!} - \frac{.1^{10}}{10!} + \frac{.1^{12}}{12!}$

Oh oops.. I was not accounting for the .1 in my error term, so that makes this allot simpler.