What are scalar multiples and projections in vector operations?

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SUMMARY

The discussion focuses on scalar multiples and projections in vector operations, specifically using the vector L = c[2, 1, 2]T. Participants clarify that every vector in L is a scalar multiple of <2, 1, 2>, with the line defined by these multiples passing through the origin. The conversation also addresses the process of finding the projection of a vector v onto L and the reflection of v across L, emphasizing the need to calculate the angle between v and L and to use the cross product to determine the plane formed by v and L.

PREREQUISITES
  • Understanding of vector operations, including scalar multiplication
  • Familiarity with vector projection techniques
  • Knowledge of cross product calculations
  • Basic concepts of angles between vectors
NEXT STEPS
  • Study vector projection formulas and their applications
  • Learn about the geometric interpretation of scalar multiples in vector spaces
  • Explore the cross product and its role in determining vector planes
  • Investigate reflection of vectors across lines in three-dimensional space
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Students and professionals in mathematics, physics, and engineering who are working with vector operations, particularly those focusing on linear algebra and geometric interpretations of vectors.

lypaza
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[PLAIN]http://img62.imageshack.us/img62/5319/49966749.png

What is the scalar multiples of a vector actually?
I was thinking L = c[2 1 2]T
Then I looked for projection of v on L. But I got c in my answers which are not supposed to be...
 
Last edited by a moderator:
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lypaza said:
[PLAIN]http://img62.imageshack.us/img62/5319/49966749.png

What is the scalar multiples of a vector actually?
I was thinking L = c[2 1 2]T
Then I looked for projection of v on L. But I got c in my answers which are not supposed to be...
Every vector in L is some scalar multiple of <2, 1, 2>. The line goes through the origin - the zero multiple of this vector is 0<2, 1, 2> = <0, 0, 0>, a vector that starts and ends at the origin. The line goes through the point (-4, -2, -4), which you can get by taking the -2 multiple of the vector.

For the reflection of v in the line, you want to find another vector w that is in the same plane as v and L, but is on the opposite side of L, and makes the same angle with L.
 
Last edited by a moderator:
So I have to find angle theta between v and L, and then find vector w with negative theta?
I also have to find the plane of v and L by cross product of v and L ...
 
Last edited:

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