Understanding aspect ratio along-with xlim,ylim in Plot.jl

New to Julia
1 
g(x) = x^4
fig1 = plot(g, xlim=(-20,20),ylim=(-20,20),aspect_ratio=:equal)
fig2 = plot(g, -20,20)#aspect_ratio=:equal
fig3 = plot(fig1, fig2, layout = (1, 2), legend = false)

fig-2

Question: How to ensure equal aspect ratio in right figure? Figure on the left is not useful due to non smoothness plot.

Kind regards

2

The non-smoothness is due to the automatic choice of evaluation points by the plot function. If the function is given a more explicit x-axis range, it fixes this issue. So, the following might fix the problem:

fig1 = plot(g, -3,3; xlim=(-20,20),ylim=(-20,20),aspect_ratio=:equal)