函數(shù)y=|x+2|-|x-2|是什么函數(shù) A 奇函數(shù) B 偶函數(shù) C既是奇函數(shù)又是偶函數(shù) D 非奇非偶函數(shù)
將函數(shù)y=|x+2|-|x-2|變?yōu)榉侄魏瘮?shù):
x<=-2時(shí),y=-x-2-(2-x)=-4;
-2
x>2時(shí),y=x+2-(x-2)=4.
再考察f(-x)=l-x+2l-l-x-2l
x<=-2時(shí),y=-x+2-(-2-x)=4;
-2
x>2時(shí),y=x-2-(x+2)=-4.
可見,f(-x)=-f(x),所以原函數(shù)是奇函數(shù).答案選A