0因为yn≤zn,所以zn-yn≥0,所以lim(n→∞)(zn-yn)≥0因为xn≤yn,所以xn-yn≤0,所以lim(n→∞)(xn-yn)≤0因为lim(n→∞)(zn-xn)=0,所以lim(n→∞)(zn-yn)=lim(n→∞)[(zn-xn)+(xn-yn)]=lim(n→∞)(zn-xn)+lim(n→∞)(...