已知向量 OA =(2 2 ,0),O是坐标原点,动点 M 满足:| OM + OA |+| OM - OA |=6. (1)求点 M 的轨迹 C 的方程; (2)是否存在直线 l 过 D(0,2)与轨迹 C 交于 P、Q 两点,且以 PQ 为直径的圆过原点,若存在,求出直线 l 的方程;若不存在,说明理由.
【单选题】Middle Age: A Low Point for Most People around the globe hit the height of their misery and depression in middle 【51】______, a new international study suggests. The finding by British and American res...