已知y=f（x）是奇函数，当x＞0时，f（x）=4x则f（-12）=______

搜题请搜索小程序“爱下问搜题”

问题填空题

已知y=f（x）是奇函数，当x＞0时，f（x）=4^x则f（-

）=______．

答案

∵y=f（x）是奇函数，

当x＞0时，f（x）=4^x，

∴f（-

）=-f（

）

=-4

=-2．

故答案为：-2．

选择题

Judging from his IQ and his present state of study, he _____ be admitted to Tsinghua University this year

if nothing special happens. [ ]

A. should

B. shall

C. can

D. must

填空题

在水浸探伤中，探头与工件之间的水距应使二次界面回波显示在（）之后。