单选题如果奇函数f（x）在区间[a，b]（0＜a＜b）上是增函数，且最小值为2，那么f（x）在区间[－b，－a]上是（ ）．A增函数且最小值为－2B增函数且最大值为－2C减函数且最小值为－2D减函数且最大值为－2
单选题
如果奇函数f（x）在区间[a，b]（0＜a＜b）上是增函数，且最小值为2，那么f（x）在区间[－b，－a]上是（ ）．
A
增函数且最小值为－2
B
增函数且最大值为－2
C
减函数且最小值为－2
D
减函数且最大值为－2
参考解析
解析：
由于奇函数的图象关于坐标原点对称，借助图象（可作一草图，略），可知函数在原点两边定义域对称的范围内，其函数增减性一致．因此f（x）在[－b，－a]上也是增函数．而原点右边某一区间上的最大（小）值C，对称过去应为原点左边相应区间的最小（大）值－C．
由于奇函数的图象关于坐标原点对称，借助图象（可作一草图，略），可知函数在原点两边定义域对称的范围内，其函数增减性一致．因此f（x）在[－b，－a]上也是增函数．而原点右边某一区间上的最大（小）值C，对称过去应为原点左边相应区间的最小（大）值－C．
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