Question

如何把二次函数解析式y=ax²+bx+c配方成y=a﹙x-h﹚²+k的形式？

Answer 1

y
=ax^2+bx+c
=a[x^2+ (b/a)x] +c
=a[x^2+ (b/a)x + b^2/(4a^2) ] +c -b^2/(4a)
=a[ x+ b/(2a) ]^2 +c -b^2/(4a)
h=-b/(2a), k =c -b^2/(4a)