先确定下列抛物线的开口方向、对称轴及顶点,再描点画图(先配平,化为y=a(x-h)²+k(1)y=-3²+12x-3:; (2)y=4x²-24x+26; (3)y=2x²+8x-6; (4)y=1/2x²-2x-1
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![先确定下列抛物线的开口方向、对称轴及顶点,再描点画图(先配平,化为y=a(x-h)²+k(1)y=-3²+12x-3:; (2)y=4x²-24x+26; (3)y=2x²+8x-6; (4)y=1/2x²-2x-1](/uploads/image/z/6089792-32-2.jpg?t=%E5%85%88%E7%A1%AE%E5%AE%9A%E4%B8%8B%E5%88%97%E6%8A%9B%E7%89%A9%E7%BA%BF%E7%9A%84%E5%BC%80%E5%8F%A3%E6%96%B9%E5%90%91%E3%80%81%E5%AF%B9%E7%A7%B0%E8%BD%B4%E5%8F%8A%E9%A1%B6%E7%82%B9%2C%E5%86%8D%E6%8F%8F%E7%82%B9%E7%94%BB%E5%9B%BE%EF%BC%88%E5%85%88%E9%85%8D%E5%B9%B3%2C%E5%8C%96%E4%B8%BAy%3Da%EF%BC%88x-h%EF%BC%89%26%23178%3B%EF%BC%8Bk%281%29y%3D-3%26%23178%3B%EF%BC%8B12x-3%3A%EF%BC%9B+%282%29y%3D4x%26%23178%3B-24x%2B26%EF%BC%9B+%EF%BC%883%EF%BC%89y%3D2x%26%23178%3B%2B8x-6%EF%BC%9B+%EF%BC%884%EF%BC%89y%3D1%2F2x%26%23178%3B-2x-1)
先确定下列抛物线的开口方向、对称轴及顶点,再描点画图(先配平,化为y=a(x-h)²+k(1)y=-3²+12x-3:; (2)y=4x²-24x+26; (3)y=2x²+8x-6; (4)y=1/2x²-2x-1
先确定下列抛物线的开口方向、对称轴及顶点,再描点画图(先配平,化为y=a(x-h)²+k
(1)y=-3²+12x-3:; (2)y=4x²-24x+26; (3)y=2x²+8x-6; (4)y=1/2x²-2x-1
先确定下列抛物线的开口方向、对称轴及顶点,再描点画图(先配平,化为y=a(x-h)²+k(1)y=-3²+12x-3:; (2)y=4x²-24x+26; (3)y=2x²+8x-6; (4)y=1/2x²-2x-1
(1)是y=-3x²+12x-3
=-3(x²-4x+4)+12-3
=-3(x-2)²+9
(2)y=4(x²-6x+9)-10
=4(x-3)²-10
(3)y=2(x²+4x+4)-14
=2(x+2)²-14
(4)y=1/2(x²-4x+4)-3
=1/2(x+2)²-3.
这是人教版的习题:
⑴y=-3x^2+12x-3=-3(x^2-4x)-3=-3(x^2-4x+4-4)-3=-3(x-2)^2+9
抛物线开口向下,对称轴是x=2,顶点坐标为:(2,9)
⑵y=4x^2-24x+26=4(x^2-6x)+26=4(x^2-6x+9-9)+26=4(x-3)^2-10
抛物线开口向上,对称轴是x=3,顶点坐标为:(-3,10)
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这是人教版的习题:
⑴y=-3x^2+12x-3=-3(x^2-4x)-3=-3(x^2-4x+4-4)-3=-3(x-2)^2+9
抛物线开口向下,对称轴是x=2,顶点坐标为:(2,9)
⑵y=4x^2-24x+26=4(x^2-6x)+26=4(x^2-6x+9-9)+26=4(x-3)^2-10
抛物线开口向上,对称轴是x=3,顶点坐标为:(-3,10)
⑶y=2x^2+8x-6=2(x^2+4x)-6=2(x^2-4x+4-4)-6=2(x-2)^2-14
抛物线开口向上,对称轴是x=2,顶点坐标为:(2,-14)
⑷y=1/2x^2-2x-1=1/2(x^2-4x)-1=1/2(x^2-4x+4-4)-1=1/2(x-2)^2-3
抛物线开口向上,对称轴是x=2,顶点坐标为:(2,-3)
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