lim(1/(x-1)-2/(x平方-1) x趋近于1
问题描述：
lim(1/(x-1)-2/(x平方-1) x趋近于1
答
1/(x-1)-2/(x^2-1)=(x+1-2)/(x^2-1)=1/(x+1)……∵x-1≠0
原式=1/2当x→1时
答
lim(x->1)[1/(x-1)-2/(x^2-1) ]
=lim(x->1)(x-1)/(x^2-1)
=lim(x->1)1/(x+1)
=1/2