A.若A2=0,則A=0B.(AB)2=A2B2C.若AX=AY ,則X=YD.若A+X=B ,則X=B-A
A.cosx2B.-cosx2C.2xcosx2D.-2xcosx2
A.基本初等函數(shù)都是單調(diào)函數(shù)B.偶函數(shù)的圖形關(guān)于坐標(biāo)原點(diǎn)對(duì)稱C.奇函數(shù)的圖形關(guān)于坐標(biāo)原點(diǎn)對(duì)稱D.周期函數(shù)都是有界函數(shù)