《中学生数学》2010年8月(上)封三《利用方差非负性巧解求最值》一文,短小精悍,创意新颖,但美中不足的是问题2“求函数y=槡5-2x+槡3+2x的最大值”的解题过程中,没有带出最小值.事实上,这个题目是有最小值的,利用文中的方法是无法获解最小值的.课间我们经过讨论,获得了解决最小值的几个方案,不仅通俗易懂,而且能够“一石二鸟”. “Junior high school mathematics” in August 2010 (on) Feng three “the use of variance non-negative clever solution of the most value,” a short and pithy, innovative ideas, but the fly in the ointment is the problem 2 “function y = 槡 5-2x + 槡 3 +2 x maximum ”solution process, did not bring out the minimum value.In fact, the problem is the minimum value, the method used in the paper is unable to get the minimum value.We discussed after class, obtained Solve the minimum of several programs, not only easy to understand, but also to “one stone two birds.”