Question

用配方法将二次函数y＝ax2+bx+c化成y＝a(x-h)2+k的形式

写出顶点坐标

Answer 1

y = ax²+bx+c
= a(x²+b/ax)+c
= a[x-b/(2a)]²-b²/(4a)+c
= a[x-b/(2a)]²+(4ac-b²)/(4a)

Answer 2

y=ax²+bx+c
=a(x²+bx/a+b²/4a²)+c-b²/4a
=a(x+b/2a)²+(4ac-b²)/4a