*‘Lingering’*, because they never answered them in grade school or high school.

The closer you slowly travel to the North Pole (or South Pole, for that matter), the slower the earth revolves. When you finally reach dead center, i.e., when you reach the **point** (deliberate mathematical term, here), does the motion finally just STOP? I know I should know the answer, but again, no one ever taught me:o.

Also, I have a few questions about three-dimensional Cartesian coödinates (right term?).

For example, x[SUP]2[/SUP]+y[SUP]2[/SUP]+z[SUP]2[/SUP] is a three-dimensional circle, in other words a sphere (or should they all be cubed–whatever:smack:). How do you represent just a line in three-dimensional space? I think z=1, e.g., is a plane, isn’t it? And please, feel free to offer a crash course in three-dimensional geometry as well. I for one would welcome it. (Also, I was about to ask, how you represent a point in three-dimensional space. But that’s easy, isn’t it? (1, 1, 1) would be a point, wouldn’t it?)

BTW, another thing that would be a point, would be where three planes intersect, no?

I know, where two planes intersect, is a line (they did tell us that much in HS geometry:rolleyes:). At first, I though therefore, four lines intersecting, would be a point. But actually, I think it would be just three. Am I right?

Thank you in advance for your nice replies:). And this one may require a lot of math and illustration. So let me say in advance, feel free to do so:). Thank you again.

:):)