证明:当x大于等于y时,e的x次方大于等于e的y次方乘(x-y+1)
问题描述:
证明:当x大于等于y时,e的x次方大于等于e的y次方乘(x-y+1)
答
e^x-(x-y+1)e^y>0e^x-e^y+(y-x)e^y>0(e^x-e^y)/(x-y)e^y>1(e^(x-y)-1)/(x-y)>1以上是不等式等价变形,因为x>y,设x-y=n,则n>0下面证明(e^n-1)/n>1对f(n)=(e^n-1)/n求导,得f(n)导=[(n-1)e^n +1]/(n^2)显然有(n-1)e^n>-1...