A.駐點(diǎn) B.極值點(diǎn) C.間斷點(diǎn) D.可微點(diǎn)
若f(x)在[a,b]上連續(xù),a<x1<x2<x3<b,則在[x1,x3]上必有ξ,使f(ξ)=。又,本題可作怎樣的推廣?