求lim(x趋向于3时)sin(x-3)/(x的平方减9)
问题描述:
求lim(x趋向于3时)sin(x-3)/(x的平方减9)
答
lim(x趋向于3) sin(x-3)/(x*x-9)=lim(x趋向于3) sin(x-3)/[(x-3)(x+3)]
=[lim(x趋向于3) sin(x-3)/(x-3)]*[lim(x趋向于3)1/(x+3) ]
=1*1/6
=1/6