limf(x)/g(x)=0,f(x)是g(x)的高阶无穷小limf(x)/g(x)=常熟,f(x)是g(x)的通解为无穷小limf(x)/g(x)=无穷大,f(x)是g(x的低阶无穷小。比如f(x)=x^2,g(x)=xlimx-0 x^2/x=limx-0 x=0f(x)是g(x)的高阶无穷小f(x)=2x+3,g(x)=x-1limx-0 f(x)/g(x)=limx-0 (2x+3)/(x-1)=3/(-1)=-3.是常熟f(x)是g(x)的同届无穷小f(x)=x^2,g(x)=x^3limx-0 f(x)/g(x)=limx-0 x^2/x^3=limx-0 1/x=无穷f(x)是g(x)的低阶无穷小。