(p-1)x＜4x+p-34x-(p-1)x＞p-3(5-p)x＞p-3因?yàn)椋簆∈[-1,4]所以：5-p∈[1,6]因此有：x＞(p-3)/(5-p)設(shè)：f(p)=(p-3)/(5-p)f'(p)=[(5-p)+(p-3)]/(5-p)²=2/(5-p)²可見(jiàn),恒有f'(p)＞0即：f(p)恒為單調(diào)增函數(shù)而：...高一新生 看不懂什么是單調(diào)函數(shù) - -1、單調(diào)增函數(shù)：又稱(chēng)單調(diào)遞增函數(shù)。其定義是：對(duì)于函數(shù)f(x)，當(dāng)x1＞x2時(shí)，恒有f(x1)＞f(x2)；2、單調(diào)減函數(shù)：又稱(chēng)單調(diào)遞減函數(shù)。其定義是：對(duì)于函數(shù)f(x)，當(dāng)x1＞x2時(shí)，恒有f(x1)＜f(x2)；3、增函數(shù)：定義是：對(duì)于函數(shù)f(x)，當(dāng)x1＞x2時(shí)，恒有f(x1)≥f(x2)；4、減函數(shù)：定義是：對(duì)于函數(shù)f(x)，當(dāng)x1＞x2時(shí)，恒有f(x1)≤f(x2)；