Sage Math is a free, open-source computer algebra system. You can install it on any device and do any kind of math at no cost!
[ Brandon's Sage Math installation guide]
ffmpeg no longer has an installation candidate in the Ubuntu 14.04 repositories:
NOTE: will not work if you reference ffmpeg in your code! sudo apt-get install libav-tools
sudo add-apt-repository ppa:mc3man/trusty-media sudo apt-get update sudo apt-get install ffmpeg gstreamer0.10-ffmpeg
NOTE: doesn't provide GStreamer-ffmpeg integration! sudo apt-add-repository ppa:jon-severinsson/ffmpeg sudo apt-get update sudo apt-get install ffmpeg
Please see my Sage Math tutorials for an introduction to what Sage can do.
Publishing from Sage
Is there an easy way to publish Sage documents and their output to PDFs/LibreOffice documents so that I can edit and comment on them to turn in as homework?
SageMathCloud notebook: You can use markdown (https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet) or html right inside a notebook cell by typing %md or %html at the beginning of the cell; when evaluated, it'll hide the markup and display the results. You can use this to comment up your work. SageMathCloud has a Print button too, just to the left of 'History' and 'Save' (see attachment). Worksheets can also be published publicly and viewed by anyone: http://goo.gl/m6gl1N Local Install notebook: %md hasn't been added to the latest release, but %html has; you can also insert richtext cells. The 'Print' button is the leftmost in the view selection ribbon. Terminal Mode (local or cloud): A final option is to do everything in text in the terminal and output any graphics with .save('filename'). The text can then be copied-and-pasted and the images inserted into your word processor of choice. SageMathCloud also has a fully-functional LaTeX editor built in. SageTex brings it all together: http://www.sagemath.org/doc/tutorial/sagetex.html