§4.2.2傅立叶级数的表示方式 Frequencies:-2 3 Formulas:c,e-22xit Ce-12mit -1 From: 3Blue1Brown https://www.youtube.com/watch?v=r6sGWTCMz2k §4.2.2 傅立叶级数的表示方式 From: https://www.youtube.com/watch?v=r6sGWTCMz2k