# Thread: The intersection between two lines

1. ## The intersection between two lines

Hi all, another vector related problem; I have two vectors x = s(1,2,1) and x = r(-6,2,2). I know they are orthogonal because their dot product is 0. But when i equate their components. i get s = -6r, 2s = 2r and s = 2r. Cannot figure out how to solve that one, should i have atleast one equation that does not contain on of the two variables? Thanks.

EDIT:
The only value of r and s that i can see satisfies both equations is 0.

2. Originally Posted by Oiler
Hi all, another vector related problem; I have two vectors x = s(1,2,1) and x = r(-6,2,2). I know they are orthogonal because their dot product is 0. But when i equate their components. i get s = -6r, 2s = 2r and s = 2r. Cannot figure out how to solve that one, should i have atleast one equation that does not contain on of the two variables? Thanks.

EDIT:
The only value of r and s that i can see satisfies both equations is 0.
Can you type out the question you verbatim?

I don't exactly understand what you are trying to accomplish.

3. hi dwsmith, the question is not out of the book. I was playing around with graphing software and wanted to find the intersection of those two vectors. Thanks for your constant help.

4. Originally Posted by Oiler
hi dwsmith, the question is not out of the book. I was playing around with graphing software and wanted to find the intersection of those two vectors. Thanks for your constant help.
Are r and s scalars? If so, are they positive or negative?

5. sorry wasn't clear, its two lines in vector form, in 3-space. x1 = s(1,2,1) and x2 = r(-6,2,2). I get them into parametric form and equate them. Just not sure on how to solve for x,y,z.