For small values of $x$, how good is the approximation $cos(x)\approx 1$
How would one tackle this problem? I've found the Taylor expansion to be $cos(x) \approx 1 - \frac{x^2}{2!} + \frac{x^4}{4!} - \frac{x^6}{6!} + \frac{x^8}{8!} - ...$, but how would one proceed?