I would say for accurate Vectors, a CAD application is the way to go.
MathCAD is worth looking into for its usage.
Autosketch seems to be a useful app', and is made by the same People that bring us AutoCAD.
This is - of course, AutoDesk, Inc.
If accuracy (for the Vector) is not required, like using the Printouts for a visual display purpose only, then any Graphics app' will work fine - something like Photoshop, Paintshop Pro, and stuff like MS Excel and/or Word.