Hello, the only thing I found to fit a sin/cos is s.th like lm(a~cos+sin) But this is not what I want. I have a magnitude which is sinusoidal with offset and it doesn't start at phi=0.
The data is: angle<-c(0,10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,180) Voltage<-c(-45.07, -45.24, -43.61, -40.78, -36.48, -30.92, -23.83, -15.95, -7.53, 1.06, 11.24,19.85, 27.00, 35.00, 42.90, 49.41, 54.62, 58.54, 60.90) I need an regression with Voltage=A*cos(angle+phi)+B. How does this work? With lm or shall I use twice Fourier? thanks Markus ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
