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## #1 2012-09-07 08:44:11

zee-f
Super Member

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### lines

I am really having trouble answering this question

If I have two lines, will they cross?  Explain fully.  What postulate helps me answer this question?

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

## #2 2012-09-07 08:47:37

bobbym
Administrator

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### Re: lines

On a plane. They can be parallel and never meet. They can intersect at 1 point. They can be the same line ( on top of each other ) and intersect at an infinite number of points.

Parallel postulate talks about parallel lines never crossing.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #3 2012-09-07 08:54:27

zee-f
Super Member

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### Re: lines

So they can and cant? depending on the point or direction ?

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

## #4 2012-09-07 09:00:37

bobbym
Administrator

Online

### Re: lines

Yes, those are the three possibilites, provided both lines are on a plane.

In the drawing below I have shortened the lines so they look like segments to beter fit them on a screen. Remember as lines they continue on forever.

Uploaded Images

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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