31. See also : Convergence of Fourier series . 32. The fractional part function has Fourier series expansion 33. The Fourier series converges in ways similar to the [ ", ] case. 34. The sines and cosines in the Fourier series are an example of an orthonormal basis. 35. Then H [ F ( \ theta ) ] has an absolutely convergent Fourier series . 36. There is still an associated eigenfunction expansion ( similar to Fourier series versus Fourier transform ). 37. Fourier series are also applicable to subjects whose connection with wave motion is far from obvious.38. For example, the Fej�r kernels of Fourier series theory give rise to an approximate identity. 39. Subsequently he worked on multiple Fourier series , posing the question of the Bochner Riesz means. 40. Because the Dirac comb function is periodic, it can be represented as a Fourier series :
