<img src="/lqwvjeImg/4b/4bfed9a5e53a4af69bc515ee40579d0e.png"style="width:44px;height:22px;">是周期为<img src="/lqwvjeImg/a3/a3a30a778a58f0aeee55b93c0c37ff90.png"style="width:29px;height:35px;">的周期函数,它在 <img src="/lqwvjeImg/34/347845056fcd0de227c08b8770cd37c7.png"style="width:67px;height:28px;">上的表达式为<img src="/lqwvjeImg/08/08daeae025b1750de88f094780544bdc.png"style="width:180px;height:61px;">, 若<img src="/lqwvjeImg/83/83fbf23d25dd1325e6d507b09b873cee.png"style="width:46px;height:36px;">的傅里叶级数为<img src="/lqwvjeImg/6e/6e9c6ae3a526c6ecc90c69845411324d.png"style="width:210px;height:42px;">,则系数 <img src="/lqwvjeImg/1b/1b6db245ce03a80fb4a4833dd2e51733.png"style="width:37px;height:25px;">( ).<br>· <img src="/lqwvjeImg/13/13c574eb6bf1b1aa1743c2c04e104c48.png"style="width:26px;height:46px;"><br>· 0<br>· <img src="/lqwvjeImg/42/427358d5a67eef5858342444a0937781.png"style="width:26px;height:38px;"><br>· <img src="/lqwvjeImg/49/49a3bc2a12bd2f9e55d41539fdb61f1e.png"style="width:33px;height:38px;">