23.解:(Ⅰ)由??x?2?3cos?,22结合sin??cos??1消去参数?,
?y??3?3sin?,得C1的普通方程为(x?2)2?(y?3)2?9.
将x??cos?,y??sin?代入曲线C2的极坐标方程,得其直角坐标方程为x?2y?3?0. (Ⅱ)圆心到直线的距离为d?所以弦长PQ?29?5?4,
2?2?(?3)?31?4?5,
?POQ的高为原点到直线x?2y?3?0的距离d??0?2?0?31?4?35, 5所以S?POQ?13565. ??4?25524.解:(Ⅰ)由题意,知不等式2x?2m?1(m?0)的解集为[?2,2].
3111?x?m?,所以由m??2,解得m?.
222244yy(Ⅱ)不等式f(x)?2?y?2x?3,即2x?1?2?y?2x?3,
224y也即2x?1?2x?3?2?y.
2由2x?2m?1,得?m?2x?1?2x?3?(2x?1)?(2x?3)?4.
因为对任意y?R,2?0,yy4?0, y2则2?444yy2?,当且仅当,即y?1时等号成立, ?22??4yyy222y所以2x?1?2x?3?2?
44yf(x)?2??2x?3. ,即
2y2y