【正文】
)s i n(c osc oss i n2c oss i n1)s i n(c oss i n2t a n1s i n2c oss i n2 2 ?????????????xxxxxxxxxxxxxxx.....................................................12 分 解法二 ：（ 1）聯(lián)立方程?????????.1cossin,51cossin22 xxx .................................................................................3 分 由①得 ,cos51sin xx ?? 將其代入②，整理得 ,012c o s5c o s25 2 ??? xx ??????????????????.54c o s,53s i n, o s53c o sxxxxx ??或 故 .57cossin ??? xx ...............................................................................6 分 （