Exploring Vector Operations: Scalar Multiples, Projections, and Cross Products

In summary, the conversation discusses the scalar multiples of a vector and the projection of one vector onto another. It is mentioned that every vector in L is a multiple of <2, 1, 2> and that the line goes through the origin and a specific point. The topic of finding the reflection of a vector in a line is also brought up, with the suggestion to find the angle between the two vectors and the plane they make through a cross product.
  • #1
lypaza
18
0
[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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  • #2
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:
  • #3
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:

Related to Exploring Vector Operations: Scalar Multiples, Projections, and Cross Products

What is the scalar product of vectors?

The scalar product of vectors, also known as the dot product, is a mathematical operation that takes two vectors and produces a single scalar value. It is calculated by multiplying the magnitudes of the vectors and the cosine of the angle between them.

What are the properties of the scalar product?

The scalar product has several important properties, including commutativity, distributivity, and associativity. It also follows the law of cosines and the Cauchy-Schwarz inequality.

How is the scalar product useful in physics?

In physics, the scalar product is used to calculate work and energy, as well as determining the angle between two vectors. It is also used in calculating the magnitude of a vector in a specific direction.

Can the scalar product be negative?

Yes, the scalar product can be negative if the angle between the two vectors is greater than 90 degrees. This indicates that the vectors are pointing in opposite directions.

What is the geometric interpretation of the scalar product?

The geometric interpretation of the scalar product is the projection of one vector onto another. This can be visualized by drawing a right triangle between the two vectors and calculating the length of the adjacent side.

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