I put this into sagecell online and get a messed up plot. f(x) simplifies to 1.
f(x)=2/3(cos(x)^2 + cos(x-(2/3)pi)^2 + cos(x-(4/3)*pi)^2)
(plot( f , -4,4))
You are seeing the numerical noise around 1.
Try
plot(f,-4,4,ymin=0,ymax=2)Interestingly, I do not see numerical noise in (2/3*(cos(x)^2 + cos(x-(2/3)*pi)^2 + cos(x-(4/3)*pi)^2)).plot((-1, 1)), but I do see it in (2/3*(cos(x)^2 + cos(x-(2/3)*pi)^2 + cos(x-(4/3)*pi)^2)).plot((-4,4)).
Go figure...
Look: u(x)=cos(x)^2
v(x)=cos(x-(2/3)*pi)^2
w(x)=cos(x-(4/3)*pi)^2 and plot
plot((v+w+u)*2/3,-4,4)
Asked: 3 years ago
Seen: 282 times
Last updated: Sep 13 '21
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