【简答题】已知圆C过原点且与 相切,且圆心C在直线 上. (1)求圆的方程;(2)过点 的直线l与圆C相交于A,B两点, 且 , 求直线l的方程.
【简答题】已知椭圆 x 2 a 2 + y 2 b 2 =1 ,过椭圆左顶点A(-a,0)的直线L与椭圆交于Q,与y轴交于R,过原点与L平行的直线与椭圆交于P,求证:AQ, 2 OP ,AR成等比数列.
【判断题】美国人交友处事的顺序是:法律、道理、人情。
【简答题】已知直线l过点P(0,2),斜率为k,圆Q:x 2 +y 2 -12x+32=0. (1)若直线l和圆相切,求直线l的方程; (2)若直线l和圆交于A、B两个不同的点,问是否存在常数k,使得 OA + OB 与 PQ 共线?若存在,求出k的值;若不存在,请说明理由.
【单选题】What problem does the man have in taking pictures? 查看材料
A.
He can't fmd good subjects to photograph.
B.
His indoor shots are too dark.
C.
His pictures are often blurry.
D.
His camera is too big for good detail.
【单选题】肯德基分店设在伊斯兰教聚集区,因此改良菜单,用鸡肉代替猪肉,这主要受到()因素影响
【单选题】We enjoy taking pictures while .
【简答题】What problem does the man have in taking pictures?