I am a PH.D in mathematics. I am interested in finding some applications of discrete Sine/Cosine transformations (DTTs) that are based on the eigenvectors.
I have found some results concerning computing the eigenvectors of DTTs. Indeed they suggest some ways to find them approximately (See for examples Tseng and Pei).
Q. Suppose that we have determined a basis of eigen-vectors for some type of discrete Sine/Cosine transformations. Based on having this knowledge in this particular issue, what applications will be leaded to find?