设函数f(x)在【a,b】上连续且单调增加,求证∫[a ,b] xf(x)dx >=a+b/2∫[a ,b] f(x)dx
问题描述:
设函数f(x)在【a,b】上连续且单调增加,求证∫[a ,b] xf(x)dx >=a+b/2∫[a ,b] f(x)dx
答
记:g(x)=S[a,x]tf(t)dt-[(a+x)/2]S[a,x]f(t)dt,a