Question

已知二次函数y=ax^2+bx+3的图像与x轴相交于点A、C,与y轴相交于点B,A(-9/4,0),且△AOB~△BOC

Answer 1

B(0,3)

A(-9/4,0)

代入得

27a-12b+16=0

C(2/3a,0)

M(m,0)

O(m/2,3/2)

圆方程

(x-m/2)^2+(y-3/2)^2=(m/2)^2+9/4

化简

x(x-m)+y(y-3/2)=0

BC方程

y=(-9a/2)x+3

求P(p,-4.5ap+3)