Time Shifting Property
The time shifting property states that if the periodic signal $ x(t) $ is shifted by $ t_0 $ to created the shifted signal $ x(t-t_0) $, then the Fourier series coefficients of $ x(t) $, $ a_k $, will all be multiplied by $ e^{-jkw_0t_0} $ resulting in the coefficients of the shifted function being $ a_k e^{-jkw_0t_0} $.
