兩個(gè)凸函數(shù)的復(fù)合函數(shù) 上凸函數(shù)與下凸函數(shù)怎么判斷? 2021-03-17 2648 上凸函數(shù)與下凸函數(shù)怎么判斷?對(duì)于函數(shù)y=f(x),當(dāng)自變量x 上凸函數(shù)與下凸函數(shù)怎么判斷?對(duì)于函數(shù)y=f(x),當(dāng)自變量x相反,當(dāng)自變量x凸函數(shù)的二階導(dǎo)數(shù)?凸函數(shù):斜率不斷上升,即斜率的導(dǎo)數(shù)大于0,即原函數(shù)的二階導(dǎo)數(shù)大于0凹函數(shù):斜率不斷下降,即斜率的導(dǎo)數(shù)小于0,即原函數(shù)的二階導(dǎo)數(shù)小于0小于0