Proving the Cross Product of Non-Zero Parallel Vectors is Equal to 0

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SUMMARY

The discussion centers on proving that the cross product of two non-zero parallel vectors, F and G, equals zero. Participants suggest methods for demonstrating this, including using the definition of parallel vectors where F = cG for some scalar c. The cross product is computed in three dimensions, confirming that if F and G are parallel, then F X G = 0. The conversation emphasizes the importance of understanding vector definitions and properties in vector calculus.

PREREQUISITES
  • Understanding of vector algebra and operations
  • Knowledge of the cross product in three-dimensional space
  • Familiarity with scalar multiplication of vectors
  • Basic concepts of linear dependence and parallel vectors
NEXT STEPS
  • Study the properties of the cross product in three dimensions
  • Explore the concept of linear dependence in vector spaces
  • Review definitions and examples of parallel vectors
  • Practice solving vector equations involving scalar multiplication
USEFUL FOR

Students studying vector calculus, educators teaching linear algebra, and anyone interested in understanding vector operations and their geometric interpretations.

cleopatra
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Homework Statement


F and G are not 0.
F and G are parallel
Proof that F X G is=0


Attempt for a sol:

F=(a1,b1,c1)
G=(a2,b2,c2)
FXG=...
But then I don´t know how to show that they are parallel.

Or..

Find some numbers for F and G that I know that makes them parallel and show that FXG
are=0
But I think I´m not supposed to use numbers, but a,b,c...

Would you use either one of theses attempts or not?
 
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There are several different definitions of vectors being parallel (one of them is that the outer product is zero).
So can you check your notes / textbook and tell us what it means if two vectors are parallel.

If it says something like: "F and G are parallel if there is some number c such that F = c G" then you can simply take
F = (x, y, z)
G = (cx, cy, cz)
and compute the cross product.

(Note that this is completely general because the cross product only exists in 3 dimensions)
 

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