> we'll typically just call this f_2(x) = 3x^2, "we" who? You're projecting infinitesimals down onto reals, and then complaining that the infinitesimals are go

> we'll typically just call this f_2(x) = 3x^2, "we" who? You're projecting infinitesimals down onto reals, and then complaining that the infinitesimals are gone. That seems like a "you" problem. You can keep the ifinitesimals if you don't want to lose then.