来自费良俊的问题
f(x)=(1-x)e^x-1,g(x)=f(x)/x证明g(x)有最大值g(t)且-2
f(x)=(1-x)e^x-1,g(x)=f(x)/x证明g(x)有最大值g(t)且-2


f(x)=(1-x)e^x-1,g(x)=f(x)/x证明g(x)有最大值g(t)且-2
f(x)=(1-x)e^x-1,g(x)=f(x)/x证明g(x)有最大值g(t)且-2
求导,g'(x)=((-x^2+x-1)*e^x+1)/x^2
验算知g'(-2)>0,g(-1)