⒈ ?增函數(shù)和減函數(shù)的統(tǒng)稱。當函數(shù)f(x)的自變量在其定義區(qū)間內增大時,函數(shù)值也隨著增大(或減小),則稱該函數(shù)為增函數(shù)(或減函數(shù))。