对于数的平方根 ,首先要理清知识点 ,系统地掌握好 ,才能利用其应用 .一、知识点1 .平方根的定义一个数的平方等于a ,这个数就是a的平方根 .即如果x2 =a ,那么x就叫做a的平方根 (或二次根式 ) .在这里a是x的平方数 ,它是一个正数或零 (即非负数 ,即a≥ 0 ) .例如 :∵ 3 2 =9,(- For the square root of the number, we must first sort out the knowledge points and systematically master it in order to use its application. First, the knowledge point 1. The square root definition The square of a number is equal to a, this number is the square root of a. That is if x2 = a , then x is called the square root (or quadratic root) of a. Here where a is the square of x, it is a positive number or zero (ie non-negative, ie a ≥ 0). For example: ∵ 3 2 = 9, (-