设f(x)在[a,b]连续且f′(x)>0,证明∫(a,b) xf(x)dx≥(a+b)/2 ∫(a,b)f(x)dx

设f(x)在[a,b]连续且f′(x)>0,证明∫(a,b) xf(x)dx≥(a+b)/2 ∫(a,b)f(x)dx 设f‘(x)在[a,b]上连续,且f(a)=0,证明:|∫b a f(x)dx| 设f(x)在[a,b]上连续,且f(x)>0,证明:∫b a f(x)dx*∫b a 1/f(x)dx≥(b-a)^2 设f(x) 在[a,b] 上连续,且f(x)>0.求证:∫(a,b)f(x)dx*∫(a,bdx/f(x)≥(b-a)^ 定积分的证明设函数f(x)在[a,b]上连续且单调递增,求证：∫[b,a] xf(x)dx≥[(a+b)/2]∫[b,a 设f(x)在区间 [a,b]上连续,证明1/(b-a)∫f(x)dx≤(1/(b-a)∫f²(x)dx)^&# 设f(x)在[a,b]上连续,且f(b)=a,f(a)=b,证明∫(上b下a)f(x)f'(x)dx=1/2(a 设f(x)在区间[a,b]上连续,证明∫上限a,下限b.f(x)dx=∫上限a,下限bf(a+b-x)dx. 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)d 设f(x)在[a,b]上连续,且严格单增,证明:(a+b)∫(上b下a)f(x)dx 设函数f(x)在区间[a,b]上连续,证明:∫f(x)dx=f(a+b-x)dx 设f(x)在[a,b]上连续,且f(x)＞0,证明：至少存在一点ξ∈(a,b),使得∫f(x)dx=∫f(x)dx.(左