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Exam question t/f 2

  • Thread starter Mdhiggenz
  • Start date
  • #1
327
1

Homework Statement



I just remembered another question that I wasn't to sure about

1) if n1xn2 does not intersect the plan then n1xn2=0
I chose false for this one.

thoughts?



Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
6,054
390
What are n1 and n2, and what is "the plan"?
 
  • #3
327
1
Plane* sorry, n1, and n2 and vectors.
 
  • #4
6,054
390
What plane is this? n1 x n2 is a vector, and for any given vector there are infinitely many planes it does not intersect.
 
  • #5
327
1
Its a true or false question, don't know what else to tell you.
 
  • #6
6,054
390
What is "the" plane in the question? Or was that really "a" plane?
 
  • #7
33,081
4,783
I'm guessing that n1 and n2 are vectors in the plane, and "intersect" means that it (n1 x n2) intersects at a single point.
 
  • #8
327
1
Indeed Mark.
 
  • #9
LCKurtz
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Its a true or false question, don't know what else to tell you.
You could tell us the complete and exact wording of the question. I have read up through post #8 and I still have no idea what this is about.
 
  • #10
327
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Honestly that is exactly how the question was worded.
 
  • #11
33,081
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Since you're going by what might be an imperfect memory of the problem statement, let's assume that it was as I said.

IOW, n1 and n2 are vectors in a plane. If n1 X n2 does not intersect the plane at a single point, then n1 X n2 = 0.
 
  • #12
327
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Ugggg why put true or false on a math exam....
 
  • #13
LCKurtz
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What a poorly worded question then. Vectors don't intersect planes. Lines with the given vector as a direction vector might. It would better be stated as the contrapositive: If ##\vec n_1 \times \vec n_2 \ne \vec 0## a line with that direction vector intersects the plane in exactly one point.
 

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