Question

根据下列条件,求二次函数的解析试

Answer 1

1.设解析式为y=ax^2+bx+c

则:{-2=a+b+c}

{-3=c}

{-6=a-b+c}

即 a=-1,b=2,c=-3

y=-x^2+2x-3

2.设解析式y=a(x-3)^2+5过(1,11)

则; 11=4a+5

a=3/2

y=3/2x^2-9x+37/2

3.设解析式y=a(x-1+根号2)(x-1-根号2)过(0,-2)

则; -2=a(-1+根号2)(-1-根号2)

a=2

y=2x^2=4x-2