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I am trying to generate a plot for S2[w]. My code is below
L := 50
Umc := 4.31
Su[ω_, σ_, τ_] := (σ^2 *τ/π )*1/(1 \
+ (τ *ω)^2)
Sw[ω_, σ_, τ_] := (σ^2 *τ/(2*π \
))*(1 + 3*(τ* ω)^2)/(1 + (τ*ω)^2)^2
Ru[s_] := InverseFourierTransform[Su[ω, 1, L/Umc], ω, s]
S2 [ω_] := Integrate[Ru[s]*Cos[2*ω*s], {s, 0, Infinity}]
Plot[S2[ω] , {ω, 0, 1}]
I have no idea what I am doing wrong. The function outputs number for the prescribed range when I tested. Your help would be much appreciated. Thanks!
Plot[Evaluate@S2[ω], {ω, 0, 1}, PlotRange -> All]
BTW, generally a bad idea to use symbols with capitalized initials - you risk clashing with built-in symbols...
S3[w] on the same graph then can you please help me with this? I tried Plot[{Evaluate@S2[\[Omega]], Evaluate@S3[\[Omega]]}, {\[Omega], 0, 1}, PlotRange -> All] but it doesn't work. where S3[\[Omega]] = Integrate[Ru[s]*Cos[\[Omega]*s], {s, 0, Infinity}]...also I would like to have the x axis in log scale...can you please help with this? thanks
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Evaluate should be placed at the first level inside the function with a Hold* attribute you wish to cancel (Plot in this case): Plot[Evaluate@{S2[\[Omega]], S3[\[Omega]]}, {\[Omega], 0, 1}, PlotRange -> All].
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Mar 23, 2014 at 1:19
LogLogPlot[Evaluate@S2[\[Omega]], {\[Omega], 0, 1}] but there is an error...can you please help with this? sorry for the bother
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LogLogPlot[Evaluate@{S2[\[Omega]], S3[\[Omega]]}, {\[Omega], 0, 1}, PlotRange -> All]) for many plots then will it still work? I'll really appreciate the help...just need this result
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LogLogPlot you get the message "Range specification {ω,0,1} is not of the form {x, xmin, xmax} with xmin and xmax positive." which simply means that you must specify the plotting range with positive boundaries because Log is Real only for positive argument. So you should use something like LogLogPlot[Evaluate@S2[\[Omega]], {\[Omega], 0.01, 1}]. Answering your second question, yes, it should work.
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Mar 25, 2014 at 19:17
Plot[Evaluate@S2[\[Omega]], {\[Omega], 0, 1}, PlotRange -> All]$\endgroup$