问题
选择题
将抛物线y=2x2-12x+16绕它的顶点旋转180°,所得抛物线的解析式是( )
A.y=-2x2-12x+16
B.y=-2x2+12x-16
C.y=-2x2+12x-19
D.y=-2x2+12x-20
答案
y=2x2-12x+16=2(x2-6x+8)=2(x-3)2-2,
将原抛物线绕顶点旋转180°后,得:y=-2(x-3)2-2=-2x2+12x-20;
故选D.
将抛物线y=2x2-12x+16绕它的顶点旋转180°,所得抛物线的解析式是( )
A.y=-2x2-12x+16
B.y=-2x2+12x-16
C.y=-2x2+12x-19
D.y=-2x2+12x-20
y=2x2-12x+16=2(x2-6x+8)=2(x-3)2-2,
将原抛物线绕顶点旋转180°后,得:y=-2(x-3)2-2=-2x2+12x-20;
故选D.