摘要
考查函数
y=x^2．
我们将建立它的基本性质并构造出它的曲线图．1．对x的所有取值函数都有定义并且总是非负的，当x=0时函数值等于0，同时当x取其他值时函数值为正．因此，函数图象过原点并落在x轴之上（唯一公共点0（0，0），即为原点）．．
Consider the function
y=x^2.
We will establish its elementary properties and construct its graph.
1. The function is defined for all values of x and is nonnegative,being equal to zero for x= 0 and positive for any other values of x. Hence, the graph of the function passes through the origin and lies above the x-axis （the only common point,O（0,0） ,being at the origin）.
