设<img src="https://static.zxtiku.com/wangke/imgs/topic/61ebc94be10689af44ae5388a1c1a1c3.png"/>是以2为周期的周期函数，那么<img src="https://static.zxtiku.com/wangke/imgs/topic/870a76deda2c285a6d5ded5dace017e2.png"/>的傅里叶级数在<img src="https://static.zxtiku.com/wangke/imgs/topic/338bc5ea5267ac0cd4f4cbdfee4ab853.png"/>处和<img src="https://static.zxtiku.com/wangke/imgs/topic/8661cef2754ae878dc070998cd169770.png"/>处分别收敛于