Hello, everybody.
I found a solution a few days after asking this question, but I couldn't post it until now.
When we write

```
p = plot(x^2) + plot(x^3)
```

Sage creates a list of two "line groups". For example, if we write `p[0]`

, Sage answers something like "Line defined by 223 points". This is actually the set of points that define the curve for $x^2$. Similarly, p[1] is the set of points for $x^3$ .

Now, we can access the options associated with each line set with

```
p[i].options()
```

where i=0 or i=1 in this case. We will receive an answer like

{'alpha': 1,
'legend_color': None,
'legend_label': None,
'rgbcolor': (0, 0, 1),
'thickness': 1}

As we can see, there is a field called "rgbcolor", which has a triplet associated. We can change that with any values we want, and use the `set_options`

command to set the new configurations. (There are other properties that can be manually changed.)

Next, I give an example of how to change the color of both function graphs to green:

```
p = plot(x^2) + plot(x^3)
for plt in p:
opt = plt.options()
opt['rgbcolor'] = Color('green')
plt.set_options(opt)
```

I hope this helps to whoever needs to change colors (or other attributes) AFTER calling `plot`

.

probably not possible