急求!lim(x3-3x+2)/(x4-4x+3)在x趋于1的时候的极限

问题描述:

急求!lim(x3-3x+2)/(x4-4x+3)在x趋于1的时候的极限

lim(x3-3x+2)/(x4-4x+3)=lim(x^3-x^2+x^2-3x+2)/(x^4-x^2+x^2-4x+3)(约掉x-1)
=lim(x^2+x-2)/(x^3+x^2+x-3)(约掉x-1)
=lim(x+2)/(x^2+2x+3)=3/6=1/2,