若对于定义在R上的函数 f ( x ),其图象是连续不断的,且存在常数 λ ( λ ∈R)使得 f ( x + λ )+ λf ( x )=0对任意实数都成立,则称 f ( x )是一个“ λ 伴随函数”.下列关于“ λ 伴随函数”的结论:① f ( x )=0不是常数函数中唯一一个“ λ 伴随函数”;② f ( x )= x 不是“ λ 伴随函数”;③ f ( x )= x 2 是“ λ 伴随函数”;④“ 伴随函数”至少有一个零点.其中正确的结论个数是( )
【简答题】Track 3-4 For many night , it’s hard to go to bed before midnight. How can a night owl go to sleep earlier and get a good night’s sleep? Here are some ideas. Some foods and drinks help you sleep. Bana...