So far as I know, Joplin does not currently support calculations and graphing from formulae.
There are other plugins that are supported which can display graphics based on text input like Mermaid etc. so I was simply wondering if such a plugin could feasibly be developed using something like PGF/Tikz.
Like 2 dimensional graph ich can greate with Wolframaplha and paste it as a picture. I would be easier or better to use if its was joplin supported. But 3 dimensional graph are a problem for me atm. Thats why I hoped I overlocked a KaTex feature or a mermaid feature. Especially if you want to start doing stuff with vector geometrie I would be kinda nice to have a visualition to show other people.
You asked it if supported TeX, I simply replied saying that it supports KaTeX - i.e. it has the capability to one degree or another to display a rendered output from text - i.e. that additional libraries etc. could be developed as plugins to perform other tasks.
The exact knowledge of how it is integrated or how to develop it is far beyond me which is why I asked the question:
Maybe this was misleading, but as I described further down, I expect KaTeX as render TeX math formulas without TeX, what very likely excludes PGF/TikZ.
As a solution for the originally asked question (»is it possible to render functions in form of math plots«) I pointed to “Function plot”, which is a JavaScript solution for function plotting.
As KaTeX shows, implementing of existing JavaScript solutions as a plugin is possible. As the attempt of turtle331 shows, \usepackage {pgfplots} obviously has no effect (as I expected).
I don't think any of the current plugins support this. But is there any JS lib that takes a math function as input and renders a graph? If so that could probably be used to create a new plugin.
I found out that math.js supports some sort of plotter but I think its more html than js. I am currently trying to implement it to Joplin. Not sure though if it works.