A:either
B:however
C:yet
D:instead
- Are you Emma's brother? ( )
- ________, I'm not.
采购数量(件)
1
2
…
A产品单价(元/件)
1480
1460
B产品单价(元/件)
1290
1280
(Ⅰ)当α= π3 时,求C1与C2的交点坐标;
(Ⅱ)过坐标原点O做C1的垂线,垂足为A,P为OA中点,当α变化时,求P点的轨迹的参数方程,并指出它是什么曲线.