Question

(1/1-x)-(3/1-x³)化简然后求X趋近于1的极限！(要详细步骤)

Answer 1

解：lim(x->1)[1/(1-x)-3/(1-x^3)]=lim(x->1)[(-(1-x)(x+2))/((1-x)(1+x+x^2))] (通分化简)
=lim(x->1)[-(x+2)/(1+x+x^2)] (分子分母同除(1-x))
=-(1+2)/(1+1+1^2)=-1。