Open source math software for Mac OS X

[Agisch]

Is there an open source math software for Mac OS X which is equivalent to Mathematica?
I intend to use it for vector geometry problems (drawing planes, lines in 3-D space).

 

[D H]

There's Maxima, which is close in some respects. It doesn't quite have the power of Mathematica, and the user interface isn't anything close to that of Mathematica's.

 

[phyzguy]

There's a Unix-based open source program called Sage which has a lot of Mathematica's functions. Since it's Unix-based, it should run on the Mac.