limx→1((1/1-x )- (3/1-x^3))

问题描述:

limx→1((1/1-x )- (3/1-x^3))
刚学

limx→1((1/1-x )- (3/1-x^3))=limx→1{(x^2+x+1)[/(1-x)(x^2+x+1)]-(3/1-x^3)}=limx→1[(x^2+x+1-3)/(1-x^3)]=limx→1[x^2+x-2)/(1-x^3)]=limx→1[(x-1)(x+2)/(1-x)(1+x+x^2)]=limx→1[-(x+2)/(1+x+x^2)]=[-(1+2)/(...