题目内容
函数y=
+1(x≥1)的反函数是( )
| x-1 |
| A.y=x2-2x+2(x<1) | B.y=x2-2x+2(x≥1) |
| C.y=x2-2x(x<1) | D.y=x2-2x(x≥1) |
∵y=
+1(x≥1)
?y≥1,
反解x?x=(y-1)2+1?x=y2-2y+2(y≥1),
x、y互换,得
?y=x2-2x+2(x≥1).
故选B.
| x-1 |
?y≥1,
反解x?x=(y-1)2+1?x=y2-2y+2(y≥1),
x、y互换,得
?y=x2-2x+2(x≥1).
故选B.
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