借助于复变数解析函数求一些三角级数的和

Sum of Some Trigonometric Series in Terms of Analytic Functions

把求三角级数的和转化为求复数域内相应幂级数的和,所要求的余弦级数的和与正弦级数的和分别等于幂级数和的实部与虚部系数.

Real trigonometric series can be transformed into power series of complex variable such that the sums of the cosine series and sine series are equal to the real and imaginary parts of the sum of power series.