一、运用根式定义法此种方法常用到二次(或偶次)根式的被开方数是非负数这一性质.例1比较2~(1/2)-a与3~(1/2)-3的大小.解由题意得二、平方法利用性质:当a>0,b>0时,若a2>b2,则a>b.例2比较5~(1/2)+13~(1/2)与7~(1/2)+11~(1/2)的大小.解 First, the use of the root definition method This method is often used to quadratic (or even) root type of the squared number is non-negative property. Example 1 Comparison 2 ~ (1/2)-a and 3 ~ (1/2) The size of -3. Solution by the meaning of the second, the use of flat nature: When a> 0, b> 0, if a2> b2, then a> b. Example 2 compare 5 ~ (1/2) + 13 ~ (1/2) and 7~(1/2)+11~(1/2) size solution