Zeros of trigonometric polynomials
( go to the article → https://www.johndcook.com/blog/2021/01/14/sturm-hurwitz/ )
A periodic function has at least as many real zeros as its lowest frequency Fourier component. In more detail, the Sturm-Hurwitz theorem says that has at least 2n zeros in the interval [0, 2π) if an and bn are not both zero. You could take N to be infinity if you’d like. Note that the […] The post Zeros of trigonometric polynomials first appeared on John D. Cook.
Jan. 15, 2021, 1:30 a.m.