A.F(x)是偶函數(shù)⇔f(x)是奇函數(shù) B.F(x)是奇函數(shù)⇔f(x)是偶函數(shù) C.F(x)是周期函數(shù)⇔f(x)是周期函數(shù) D.F(x)是單調(diào)函數(shù)⇔f(x)是單調(diào)函數(shù)
設(shè)函數(shù)f(x)連續(xù),證明: