1. The problem statement, all variables and given/known data Say x is an infinitesimal number on the hyperreal line, is this expression finite, infinite or infinitesimal 2. Relevant equations (sqrt(4+x)-2)/x 3. The attempt at a solution My approach so far has been that sqrt(4+x) is (2+y) where y is another infinitesimal and y<x, which seems to lead to the conclusion that this expression is infinite, but the answers say it's finite. Any help?