Useful software for notes and graphs in economics? I'm looking for a software which may help me to both take notes and draw graphs during university lectures. It must have the ability to switch between texts and graphs, add other formats such as Office related format and pdf. Also, the the graphs should be easily tunable (preferably on the fly) and of course, shareable. Being able to draw matrices and operate with them would be great too.

I can't seem to find an application/software for laptop which makes all of those easy in an economics related setting. Any idea?

Thanks a lot
I've been trying to find a solution for this same question.  As mentioned by others, most of the solutions are a bit too time consuming to do on the spot if you're taking notes, so I still think it's easier to draw out the graphs by hand on the spot.  

There's a good post referencing some of the different software options, along with how to do this with R and ggplot if you're interested on Andrew Heist's blog 

Also, see Create simple graphs without functional forms

Among these options, I'm trying to learn to do everything with TiKZ, but it's a work in progess...