f(x+y)=f(x)+f(y)取x=y=0,得f(0)而f(x)在x=0处连续,故lim(h->0)f(h)=f(0)=0故对任意的x,有lim(h->0)f(x+h)=lim(h->0) (f(x)+f(h))=lim(h->0) f(x) + lim(h->0) f(h)=lim(h->0) f(x)故f(x)对一切x均连续...