對(duì)實(shí)數(shù)a與b,定義新運(yùn)算“?”:a?b=
.設(shè)函數(shù)f(x)=(x
2-2)?(x-1),x∈R.若函數(shù)y=f(x)-c的圖象與x軸恰有兩個(gè)公共點(diǎn),則實(shí)數(shù)c的取值范圍是( ?。?br/>A. (-1,1]∪(2,+∞)
B. (-2,-1]∪(1,2]
C. (-∞,-2)∪(1,2]
D. [-2,-1]
∵
a?b=,
∴函數(shù)f(x)=(x
2-2)?(x-1)
=
,
由圖可知,當(dāng)c∈(-2,-1]∪(1,2]
函數(shù)f(x) 與y=c的圖象有兩個(gè)公共點(diǎn),
∴c的取值范圍是 (-2,-1]∪(1,2],
故選B.