【单选题】Which of the following industries has a low barrier to entry?
【单选题】Which of the following industries has a low barrier to entry?
【单选题】Which of the following industries has a low barrier to entry?
【判断题】自动变速器可以分为有级式、无级式、综合式三种。
【判断题】The low barriers to entry of the online world makes it possible for many second-rate writings to reach thousands of readers.
【简答题】已知直角坐标平面内点A(x,y)到点F 1 (-1,0)与点F 2 (1,0)的距离之和为4. (1)试求点A的轨迹M的方程; (2)若斜率为 1 2 的直线l与轨迹M交于C、D两点,点 P(1, 3 2 ) 为轨迹M上一点,记直线PC的斜率为k 1 ,直线PD的斜率为k 2 ,试问:k 1 +k 2 是否为定值?请证明你的结论.
【判断题】快取脂策略是企业在制定高价格的同时开展大规模促销活动的策略。( )