Definition talk:Cartesian Coordinate System

Do axes have to be infinite or straight? It seems like they wouldn't need to be, but I can't think of any examples. --Cynic 21:48, 15 November 2008 (UTC)

Good call. If they're not, then it's not strictly speaking "cartesian" coordinates. Having said that, Descartes' initial treatise considered the straight-line, perpendicular version as a "special case" that was rather easier to work with than the other cases, and everyone nowadays uses perpendicular axes unless there's a good reason not to. (Some applications of group theory make it easier to have the y-axis at 60 degrees to the x-axis, as it happens. I have got into flaming rows on the internet about whether it's "allowable" to call them x and y in these circumstances. My opinion is you can call the bloody things whatever you like as long as you specify beforehand exactly what you mean. My correspondent was distressed that I was espousing heretical thinking and used his influence to ban me from certain branches of the teaching profession.)--Matt Westwood 22:00, 15 November 2008 (UTC)