答：
y=xsin(1/x)的水平渐近线就是求x趋于无穷时的极限
y=lim(x→∞) xsin(1/x)
=lim(x→∞) sin(1/x)/(1/x)
=lim(t→0) sint/t
=1
所以：y=xsin(1/x)的水平渐近线为y=1