TITLE: What's the name of the approximation $(1+x)^n \approx 1 + xn$?
QUESTION [12 upvotes]: A good approximation of $(1+x)^n$ is $1+xn$ when $|x|n << 1$.  Does this approximation have a name?  Any leads on estimating the error of the approximation?

REPLY [2 votes]: Wikipedia calls it Binomial Approximation.