How to add diagonal line to log-log plot

[Christopher_Fisher]

@TimG

Yes, because you are trying to plot on log-log axes.

Try plot! with x rather than log_x and transform the fit data to lin using 10^(fit_x). With both in linear space you can then plot them onto your original log/log axes.

I tried with xaxis = :exp10 but that did not work. Maybe it is not an option for xaxis. What you proposed did work. Thank you for your help.

Here is the solution for future reference:

using Plots
using CurveFit
x = 1:4
y = [44,29,6,1]
log_x = log10.(x)
log_y = log10.(y)
scatter(x, y, xaxis = :log10, yaxis = :log10)
fit = curve_fit(LinearFit, log_x, log_y)
plot!(x, 10 .^(fit.(log_x)))

Thank you both for your help. I’ll mark this as the solution, but attribute it to TimG.