Time Series Forecasting, Fourier, Ensemble Method, Data Science, Signal Processing.
form, here are two sine/cosine pairs, the second pair has twice the frequency of the first pair: sin(1,freq=A-DEC) cos(1,freq=A-DEC) sin(2,freq=A-DEC) cos(2,freq=A-DEC) time 1956Q1 0.000000 1.000000 0.000000 1.000000 1956Q2 0.999963 0.008583 0.017166 -0.999853 1956Q3 0.017166 -0.999853 -0.034328