What are really helpful math resources out there on the web?
Please don't only post a link but a short description of what it does and why it is helpful.
Please only one resource per answer and let the votes decide which are the best!
big-listcomputer-algebraonline-resourcesreading-listsoft-question
What are really helpful math resources out there on the web?
Please don't only post a link but a short description of what it does and why it is helpful.
Please only one resource per answer and let the votes decide which are the best!
Best Answer
I occasionally find mathoverflow.net rather helpful.
In particular, there's a good list of answers to your specific question here.