用配方法和顶点公式法求抛物线y=3x² 2x
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∵y=x²-4x+3=x²-4x+4-4+3=(x-2)²-1∴抛物线的顶点坐标是(2,-1)令X=0,得y=3∴C(0,3)令y=0,得x²-4x+3=0(x
y=-1/4(x²-4x)-4=-1/4(x²-4x+4-4)-4=-1/4(x-2)²-3∴开口向下,对称轴x=2,顶点(2,-3)
y=3(x²+2x/3)=3(x²+2x/3+1/9-1/9)=3(x²+2x/3+1/9)-1/3=3(x+1/3)²-1/3所以开口向上对称轴是x=-1/3
配方法:y=-1/2*(x^2-6x+9)+9/2-2=-1/2*(x-3)^2+5/2对称轴x=3顶点坐标(3,5/2)抛物线开口向下,x=3时最大值y=5/2
1,用配方法求出抛物线y=x²-4x+1的对称轴和顶点坐标y=(x-2)²-3对称轴x=2,顶点(2,-3)2用配方法求出抛物线y=x²+8x+1的对称轴和顶点坐标y=(
再问:第2题再答:我没写吗
a=-3,b=-1,c=1-b/(2a)=1/(-6)=-1/6(4ac-b²)/(4a)=(-12-1)/(-12)=13/12所以顶点(-1/6,13/12)
Y=2(X^2-3/2X+9/16-9/16)-4=2(X-3/4)^2-9/8-4=(X-3/4)^2-41/8对称轴:X=3/4,顶点坐标:(3/4,-41/8),当X
y=-3x²-2x+1=--1/3(9x^2-6x+1-1)+1=-1/3(3x-1)^2+4/3,y=2x²+3x-1=1/8(16x^2+24x+9-9)-1=1/8(4x+3
y=2(x²-4x+4-4)-6=2(x-2)²-14顶点(2,-14)对称轴x=2
y=-3x²-2x+1=(-3x²-2x)+1=-3[x²+(2/3)x]+1=-3[x²+(2/3)x+(1/3)²]+1+3×(1/3)²
y=-1/2(x²-4x)=-1/2(x²-4x+4)+2=-1/2(x-2)²+2∴顶点坐标为(2,2)对称轴为x=-b/2a=2
y=x^2-4x-5=x^2-4x+4-9=(x-2)^2-9顶点是(2,-9).对称轴是x=2再答:第二问分类讨论再答:
x=1/-1=-1y=-2y=1/2(x2+2x-3)=0.5((x+1)^2-4)=0.5(x+3)(x-1)A(-3.,0)B(1,0)AB=4
∵y=2x2+3x-2=2(x2+32x)-2=2[x2+32x+(34)2]-2(34)2-2=2(x+34)2-98-2=2(x+34)2-258,∴顶点坐标是(-34,-258),对称轴是直线x
y=2x^2+4x-5=2(x∧2+2x+1-1)-5=2(x∧2+2x+1)-2-5=2(x+1)∧2-7所以抛物线的对称轴为x=-1,当x=-1时,y=-7,故抛物线的顶点坐标为(-1,-7)再问
Y=-x平方-2x+3=-(x+1)²+4顶点坐标为(-1,4)
y=(x^2+3x+(3/2)^2-(3/2)^2)=(x+3/2)^2-17/4对称轴x=3/2定点坐标(-3/2,-17/4)
/>y=2x²-3x-4=2(x²-3/2x)-4=2(x²-3/2x+9/16-9/16)-4=2[(x-3/2)²-9/16]-4=2(x-3/2)
Y=1/2(x2+2x+1-1)-5/2=1/2(x+1)2-1/2-5/2=1/2(x+1)2-3顶点:当X=-1时Y=-3对称轴:X=-1