A Fourier series is a way to represent a periodic function as an infinite sum of sine and cosine terms. These trigonometric functions serve as the fundamental building blocks for many waveforms, allowing complex shapes to be reconstructed using simpler, oscillating components. The key idea is that any reasonable periodic function, no matter how jagged or irregular, can be decomposed into a sum of these smooth waves, each with a specific frequency, amplitude, and phase. This is widely used in fie