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#1 2012-09-06 10:44:11

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

lines

I am really having trouble answering this question sad


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

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#2 2012-09-06 10:47:37

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,365

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.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

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#3 2012-09-06 10:54:27

zee-f
Member
Registered: 2011-05-12
Posts: 1,220

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

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#4 2012-09-06 11:00:37

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 86,365

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.

View Image: 2012-09-06_082550.gif

In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

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