What is the importance of periodic $\text{sine}$ and $\text{cosine}$ functions in physics?

(N/A) Periodic $\text{sine}$ and $\text{cosine}$ functions are fundamental because any complex periodic function can be expressed as a superposition (sum) of $\text{sine}$ and $\text{cosine}$ functions of different frequencies and amplitudes,a concept known as $\text{Fourier}$ series. This allows physicists to analyze complex oscillatory motions by breaking them down into simpler,manageable harmonic components.