一个机器人从数轴原点出发，沿数轴正方向，以每前进3步后退2步的程序运动．设该机器人每秒前进或后退1步，并且每步的距离是一个单位长度，xn表示第n秒时机器人在数轴上的位罝所对应的数．给出下列结论：①x3

题干

一个机器人从数轴原点出发，沿数轴正方向，以每前进3步后退2步的程序运动．设该机器人每秒前进或后退1步，并且每步的距离是一个单位长度，x_n表示第n秒时机器人在数轴上的位罝所对应的数．给出下列结论：

①x₃=3；②x₅=1；③x₁₀₈＜x₁₀₄；④x₂₀₀₇＜x₂₀₀₈，其中，正确结论的序号是（）

A：①③

B：②③

C：①②③

D：①②④

上一题下一题 0.0难度选择题更新时间:2018-05-02 08:03:34

答案(点此获取答案解析）

D

同类题5

根据短文理解，选择正确答案填空。

Jim is a junior high school student. He gets up 16:30 every morning. His home is near his school. He 2home after breakfast. He goes to school on foot. This is good for his 3. He has four lessons in the morning. He has lunch at home. After lunch he goes to school again. In the afternoon, Jim has lessons . He likes English and PE lessons. He has PE lessons on Tuesday and Friday. He is good at4football and basketball. He is also good at the high jump. His PE teacher likes5 very much. He often plays football with his classmates after school.

题干

答案(点此获取答案解析）

同类题1

同类题2

同类题3

同类题4

同类题5