Thanks again for the well explained article! The best insights for me is explaining why is it natural to define the inner product of function that way. However, is it possible to elaborate on why having discovered that cos(x) and sin(x) are orthogonal to each other helps the discovery of Fourier transformation?

## How to measure the angle between two functions

Thanks again for the well explained article! The best insights for me is explaining why is it natural to define the inner product of function that way. However, is it possible to elaborate on why having discovered that cos(x) and sin(x) are orthogonal to each other helps the discovery of Fourier transformation?