lim(1+x)的3/x+2次方,x趋向于0=lim(1+x)^(3/x +3 ) =lim(1+x)^(1/x)(x*(3/x +3))=lim(1+x)^(1/x)*(3+3x) 用重要极限=lim e^(3+3x)=e^3