若抛物线y=ax+bx+c与抛物线y=2x-4x-1的顶点重合且与y轴的交点的坐标(0,1),则抛物则抛物线y=ax²+bx=cd表达式是(速求 谢谢!)
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![若抛物线y=ax+bx+c与抛物线y=2x-4x-1的顶点重合且与y轴的交点的坐标(0,1),则抛物则抛物线y=ax²+bx=cd表达式是(速求 谢谢!)](/uploads/image/z/15098084-44-4.jpg?t=%E8%8B%A5%E6%8A%9B%E7%89%A9%E7%BA%BFy%3Dax%2Bbx%2Bc%E4%B8%8E%E6%8A%9B%E7%89%A9%E7%BA%BFy%3D2x-4x-1%E7%9A%84%E9%A1%B6%E7%82%B9%E9%87%8D%E5%90%88%E4%B8%94%E4%B8%8Ey%E8%BD%B4%E7%9A%84%E4%BA%A4%E7%82%B9%E7%9A%84%E5%9D%90%E6%A0%87%280%2C1%29%2C%E5%88%99%E6%8A%9B%E7%89%A9%E5%88%99%E6%8A%9B%E7%89%A9%E7%BA%BFy%3Dax%26%23178%3B%2Bbx%3Dcd%E8%A1%A8%E8%BE%BE%E5%BC%8F%E6%98%AF%EF%BC%88%E9%80%9F%E6%B1%82+%E8%B0%A2%E8%B0%A2%21%EF%BC%89)
若抛物线y=ax+bx+c与抛物线y=2x-4x-1的顶点重合且与y轴的交点的坐标(0,1),则抛物则抛物线y=ax²+bx=cd表达式是(速求 谢谢!)
若抛物线y=ax+bx+c与抛物线y=2x-4x-1的顶点重合且与y轴的交点的坐标(0,1),则抛物
则抛物线y=ax²+bx=cd表达式是(速求 谢谢!)
若抛物线y=ax+bx+c与抛物线y=2x-4x-1的顶点重合且与y轴的交点的坐标(0,1),则抛物则抛物线y=ax²+bx=cd表达式是(速求 谢谢!)
抛物线y=2x-4x-1的顶点为(1,-3)
设抛物线y=ax+bx+c的顶点式为y=a(x+m)²+k,
则m=-1,K=-3
即y=a(x-1)²-3
把X=0,Y=1代入得a=4,
∴y=4(x-1)²-3
即y=4x²-8x+1
由y=ax2+bx+c与y轴的交点的坐标为(0,1),代入得c=1.
抛物线y=ax2+bx+c的顶点为(-b/2a,(4ac-b2)/4a)可知:抛物线y=2x-4x-1的顶点为-b/2a=-(-4)/2*2=1,
(4ac-b2)/4a={4*2*(-1)-(-4)*(-4)}/4*2=-3,即抛物线y=ax2+bx+1的顶点为(1,-3)。即-b/2a=1,
4a-b...
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由y=ax2+bx+c与y轴的交点的坐标为(0,1),代入得c=1.
抛物线y=ax2+bx+c的顶点为(-b/2a,(4ac-b2)/4a)可知:抛物线y=2x-4x-1的顶点为-b/2a=-(-4)/2*2=1,
(4ac-b2)/4a={4*2*(-1)-(-4)*(-4)}/4*2=-3,即抛物线y=ax2+bx+1的顶点为(1,-3)。即-b/2a=1,
4a-b2)/4a=-3,解方程式可得:a1=0,a2=4.抛物线a=/0,取a=4.b=-2a=-8.抛物线y=ax2+bx+c表达式为
y=4x²-8x+1
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y=ax²+bx+c表达式是y=2x²-4x+1