Chapter 1: Sums, Products and Discrete Fourier Transform
Arithmetic series, geometric series and harmonic series play a central role in problems in theoretical and mathematical physics.
An arithmetic series is the sum of a sequence {sk}, k = 0, 1, … in which each term is calculated from the previous one by adding (or subtracting) a constant c. This means sk = sk−1 + c = sk−2 + 2c = … = s0 + c · k, where k = 1, 2, …. In particular one has (n ≥ 1)