Here's an interesting site that reminds me of Math in OpenOffice. You can use the site graphing up to 3 mathematical expressions simultaneously. Hence, it is good for visually comparing as well as inspecting. You can also control the graph characteristics. Though somewhat specialized and most people probably won't use it every day, it's very handy when the need arises.
from www.stumbleupon.com
from www.stumbleupon.com
