Question

已知函數(shù)是定義域?yàn)?i>R的偶函數(shù)，且,若在上是增函數(shù)，那么在上是

A．增函數(shù)

B．減函數(shù)

C．先增后減的函數(shù)

D．先減后增的函數(shù)

Answer 1

C

解析試題分析：∵，∴，∴函數(shù)f(x)的周期為2，又在上是增函數(shù)且為增函數(shù)，∴函數(shù)在上是減函數(shù)，∴函數(shù)在上是先增后減的函數(shù)，故選C
考點(diǎn)：本題考查了函數(shù)的性質(zhì)
點(diǎn)評(píng)：對(duì)于抽象函數(shù)性質(zhì)問(wèn)題，往往根據(jù)函數(shù)奇偶性、周期性等作出示意圖然后去解決