求分段函数在分段点的左右极限y=xsin1/x x>0 y=arccos(x-1) x
问题描述：
求分段函数在分段点的左右极限y=xsin1/x x>0 y=arccos(x-1) x
答
右极限：lim x->0+ f(x) =lim x->0+ xsin1/x =0 (有界量和无穷小的乘积)
左极限：lim x->0- f(x)=lim x->0- arccos(x-1) =arccos(-1)=π