设f(x)在[a、b]上连续且方程f(x)=0在[a、b]上无实根,试证明f(x)在[a、b]上恒为正或恒为负.

设f(x)在[a,b]上连续,且a 设f(x)在[a,b]上连续,且a 设f(x)在[a,b]上连续,且a 设函数f(x)在[a,b]上连续,在(a,b)内可导且f'(x) 设函数f(x)在[a,b]上连续,在(a,b)上可导且f'(x) 设函数f(x),g(x)在区间[a,b]上连续,且f(a) 证明设f(x)在有限开区间(a,b)内连续,且f(a+) ,f(b-)存在,则f(x)在(a,b)上一致连续. 求解：设f(x)在[a,b]上连续,且f(a)=f(b)=0,反f'(a)f'(b)>0,试证方程f(x)=0在(a,b)内至少存在一个实根. 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)^2. 设f(x)在[a,b]上连续,且没有零点,证明f(x)在[a,b]上保号 设函数f(x)在[a,b]上连续,在(a,b)可导,且f(a)*f(b)>0,f(a)*f((a+b)/2) 设函数f(x)在[a,b ]上连续,且f(a)〈a ,f(b)〉b ,证明:方程f(x)=x 在(a,b )内至少有一实根 设函数f(x)在[a,b]上连续,a 设f(x)在[a,b]上连续,a 设函数f(x)在[a,b]上连续,a 设f(x)在[a、b]上连续且方程f(x)=0在[a、b]上无实根,试证明f(x)在[a、b]上恒为正或恒为负. 设f（x）在[a,b]上连续且方程f（x）＝0在[a,b]上无实根.试证f（x）在[a,b]上恒为正或恒为负. 设f(x)在闭区间（a,b)上连续,且a