Question

要使函數y=x²-2ax+1在區間［1,2］上存在反函數,則a的取值范圍是(    )

A.a≤1                B.a≥2            C.a≤1或a≥2            D.1≤a≤2

Answer 1

C

解析：由已知得函數y=x²-2ax+1在區間［1,2］上單調,則a≤1或a≥2.