甲乙二人参加某体育项目训练，近期的五次测试成绩得分情况如图． (1)分别求出两人得分的平均数与方差； (2)根据图和上面算得的结果，对两人的训
在极坐标系中，是极点，设点，，则O点到AB所在直线的距离是 ．
已知函数求 （1）求的最小正周期； （2）函数在区间上的最大值、最小值及相应的x值。
________ the birds in the cage? A．Are B．Have C．Do D．Does
D Georgia was waking up to a new president Monday but it was also getting as its first lady a green eyed linguist from Holland who has already managed to cast a spell over the little Caucasus natio
试判断下列物质能否溶于水，能溶于水的组合是( ) ①葡萄糖 ②己醛 ③硬脂酸 ④硬脂酸钠 ⑤硬脂酸镁 ⑥乙二酸⑦ ⑧ ⑨⑩A.①④⑥⑦⑨
When I was young, I wished for a good car and a big house. That was my idea of success. I took all the advanced classes and tried to do well in the exams with my mind set on going to a key school. I
的最大值为8，则k=_____。