如何求二次函数的对称轴(find the axis of symmetry of a quadratic function)
什么是二次函数(a quadratic function)？
二次多项式函数称为二次函数。形式上，f（x）=ax2+bx+c是一个二次函数，其中a、b和c是实常数，a≠x的所有值均为0。二次函数的图形是抛物线。
如何求二次函数的对称轴
任何二次函数在y轴或平行于y轴的直线上显示横向对称性。二次函数的对称轴如下：
f（x）=ax2+bx+c，其中a，b，c，x∈R和a≠0
把x项写成一个正方形，
通过重新排列上述方程的项
这意味着，对于每个可能的值f（x），都有两个对应的x值。这可以在下面的图表中清楚地看到。
These values are located,
值的左右距离-b/2a。换句话说，对于任何给定的f（x），值-b/2a总是连接相应x值（点）的直线的中点。
因此，x=-b/2a是给定二次函数的对称轴方程，形式为f（x）=ax2+bx+c
如何找到二次函数的对称轴-示例
- 二次函数由f（x）=4x2+x+1给出。求对称轴。
x=-b/2a=-1/（2）×4)=-1/8
因此，对称轴的方程为x=-1/8
- 二次函数由表达式f（x）=（x-2）（2x-5）给出
通过简化表达式，我们得到f（x）=2x2-5x-4x+10=2x2-9x+10
我们可以推导出a=2，b=-9。因此，我们可以得到对称轴
x=—（-9）/（2）×2)=9/4
- 发表于 2021-06-27 00:49
- 阅读 ( 810 )
- 分类：科学
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