设f(x)在[a,b]上连续,f(a)=f(b)=0,f(x)在(a,b)内二阶可导,且f'+(a)>0.求证在(a,b
0在[a,b]上取x0且f(x0)≠0若f(x0)>0,则在(x0,b)上由拉格朗日中值定理得,存在"}}}'>