On Sep 12, 2010, at 10:23 PM, Aaditya Nanduri wrote:
Hello All,
I cant seem to do a trig regression in R.
The equation is as follows : y = a+b*(sin((2*pi*x/360) - c))^2
a, b, c are coefs that I want.
y, x are input vectors.
The equation I put into R: lm(y ~ sin(2*pi*x/360)^2)
This equation is missing the c and I dont get the right answer.
Take a look at section 2.3 of:
http://www.statoek.wiso.uni-goettingen.de/veranstaltungen/zeitreihen/sommer03/ts_r_intro.pdf
Or consider using time series or nonlinear modeling.
Also, I dont know how to plot the lm over the x values instead of the
indices.
Without an example of your data and what you tried it is difficult to
intuit what problems you may be facing.
--
David.
Any help is sincerely appreciated.
Thank you all very much.
--
Aaditya Nanduri
aaditya.nand...@gmail.com
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