skyturnred

## Homework Statement

So we are given the equation of a line and asked to do a bunch of stuff with it. When I get to the following question, I just don't understand what it is asking.

The line:

L=(2,2,5)+t(2,-1,1), where t is an element of the reals

Question:

Let S be the the line segment consisting of the points on L whose coordinates are all nonnegative (that is, S is the intersection of L with the first octant). Find the vector equation of S.

## The Attempt at a Solution

I don't quite understand what they're asking.. I know that at a point, all of the coordinates of the points on line L will be negative. But are they asking us to simply find a vector from the origin to the point at which this happens? Or are they asking us to find a vector along the line that represents all of these points (which doesn't make sense to me because in my mind that vector would be infinitely long).

Thanks!

HmBe

Could it just be a restriction on t?

skyturnred

I was actually thinking that too.. but it seems too simple to be worth 4 points in my assignment.

Staff Emeritus