问题
选择题
将二次函数y=-x2-2x-2经配方后得( )
A.y=-(x-1)2-3
B.y=-(x+1)2-3
C.y=-(x-1)2-1
D.y=-(x+1)2-1
答案
y=-x2-2x-2=-(x2+2x+1)+1-2=-(x+1)2-1
故选D.
将二次函数y=-x2-2x-2经配方后得( )
A.y=-(x-1)2-3
B.y=-(x+1)2-3
C.y=-(x-1)2-1
D.y=-(x+1)2-1
y=-x2-2x-2=-(x2+2x+1)+1-2=-(x+1)2-1
故选D.