Differential Equations - Mechanical Vibrations
tutorial.math.lamar.edu › Classes › DEAug 20, 2019 · \[\begin{equation}u\left( t \right) = R\cos \left( {{\omega _0}t - \delta } \right)\label{eq:eq5}\end{equation}\] where \(R\) is the amplitude of the displacement and \(\delta \) is the phase shift or phase angle of the displacement. When the displacement is in the form of \(\eqref{eq:eq5}\) it is usually easier to work with.
Fourier transform - Wikipedia
https://en.wikipedia.org/wiki/Fourier_transformIn mathematics, a Fourier transform (FT) is a mathematical transform that decomposes functions depending on space or time into functions depending on spatial or temporal frequency, such as the expression of a musical chord in terms of the volumes and frequencies of its constituent notes. The term Fourier transform refers to both the frequency domain representation and the …