Raw Object 100.` cannot be used as an iterator

Question

There's a similar question here on Mathematica Stack Exchange, however it was left unanswered and the context is not the same.

I have this code

Bcgc = 5.5;
xo = 0.00105;
lambda = 0.2063;
b = 0;
Qs = ((xo/x)^(lambda/2)E^(-b^2/2Bcgc))^2;
Plot[Qs, {1/x, 10^2, 10^8}]

I want to make a plot of exactly what shows above, Qs x 1/x. However, when I run the plot, it shows this error: Raw object 100.` cannot be used as an iterator.

Ways to fix it?

related: https://mathematica.stackexchange.com/q/44940/9490 A basic solution for your problem would be Plot[Evaluate[Qs], {x, 1/10^2,1/10^8},ScalingFunctions->{"Reciprocal"}] — Jason B., Jun 07 '22 at 18:59

score 4 · Answer 1 · answered Jun 07 '22 at 19:24

4

The first argument of the "range" argument in Plot has to be a "raw" variable, i.e., not a composite expression like 1/x. But if you define $y = 1/x$, and replace x with 1/y wherever it occurs (using the ReplaceAll operator /.), you can get what you want:

Plot[Qs /. x -> (1/y), {y, 10^2, 10^8}, AxesLabel -> {1/x, "Qs"}]

answered Jun 07 '22 at 19:24

Michael Seifert

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I still get it wrong, I did what you said, but I get a straight horizontal line in my plot – Laura Martins Jun 08 '22 at 14:02
@LauraMartins: Try clearing memory. The easiest way to do this is to go to the "Evaluation" menu and select "Quit Kernel > Local". See this answer for more details. – Michael Seifert Jun 08 '22 at 14:11
I got it now, thank you! – Laura Martins Jun 08 '22 at 19:01

Raw Object 100.` cannot be used as an iterator

1 Answers1