So currently I use Grapher for plotting equations. I’ve used it for years and it works great, but it doesn’t seem to be open source. So I looked for a FOSS alternative, but didn’t find one on F-Droid or the rest of the internet. Do you know of a FOSS alternative? What do you use? Do you prefer web applications (like Wolfram Alpha)?
You might want to check out microMathematics Plus. I last used it a few years ago. I remember being impressed by it, but thought it was way overkill for something I’d need on my phone.