[R] Fiting a trend + periodic signal

[Mohammed Ouassou]

Dear all,
I have a time series and I like to fit S(t) = T(t) + P(t) 

 T(t) = Linear Trend =  a + bt 
 P(t) = Periodic Signal = sum(Ai*cos(wt) + Bi*sin(wt) ) for i=1,...,3.



Thanks in advance,

Best  regards,