The classical criterion for the Fourier character of cosine series and sine series is generalized to complex trigonometric series. Our treatment unifies the ideas applied to cosine and sine series. A ...

Note: This only works when \(x\) is measured in radians. We are now going to look at more complex trigonometric functions where we will use the general rule: \(\int {\cos (ax + b)dx = \frac{1}{a}} ...