Engineering Analysis/Multi-Dimensional Fourier Series
The concept of the fourier series can be expanded to include 2-dimensional and n-dimensional function decomposition as well. Let's say that we have a function in terms of independent variables x and y. We can decompose that function as a double-summation as follows:
Where φij is a 2-dimensional set of orthogonal basis functions. We can define the coefficients as:
This same concept can be expanded to include series with n-dimensions.