Question

Explain the Fourier principle please

Answer 1

system is identified by its properties, and linearity, more often than not, plays a fundamental role in organizing them quantitatively. Thus, if $ \psi_1$ and $ \psi_2$ are two spatial amplitude profiles of a vibrating string, or two temporal histories of a simple harmonic oscillator, then so is the linear combination

$\displaystyle \psi =c_1 \psi_1 +c_2 \psi_2~. $