Calculating Linear Span: Vector a1 (-7, 8, 5) and Line Equation

In summary, the linear span of the vector a1 = (-7, 8, 5) is the line whose equation is x/(-7) = y/8 = z/5. The linear span is defined as the collection of all linear combinations of the given vectors, and for one vector v1, it is the set of all vectors k*v1 for any real number k. Therefore, for the point (x, y, z) to be in the span of (-7, 8, 5), it must satisfy the equations -7k = x, 8k = y, and 5k = z.
  • #1
dracolnyte
28
0

Homework Statement


(i)Show that the linear span of the vector a1 = (-7, 8, 5) is the line whose equation is
x/(-7) = y/8 = z/5

The Attempt at a Solution


The problem is, I don't know where or how to start.
 
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  • #2
Define the 'linear span of a vector'. Look it up if you have to.
 
  • #3
The linear span of a vector is the collection of all linear combinations of the vectors a1, a2..., ak
 
  • #4
Ok, so for one vector v1 it's the set of all vectors k*v1 for k any real number, right?
 
  • #5
Ya, and then?
 
  • #6
You are supposed to be helping here. Guess. (x,y,z) is a point in the span of (-7, 8, 5). What's it equal to?
 
  • #7
Okay so
-7k = x
8k = y
5k = z
 
  • #8
Got it, thank you so much. I'll be back with more for sure lol.
 

Related to Calculating Linear Span: Vector a1 (-7, 8, 5) and Line Equation

1. What is a subspace?

A subspace is a subset of a vector space that satisfies the properties of a vector space. This means that it is closed under addition and scalar multiplication, and contains the zero vector.

2. What is the difference between a subspace and a span?

A subspace is a subset of a vector space, while a span is the set of all possible linear combinations of a given set of vectors. A subspace is a subset of a span, but a span may not necessarily be a subspace.

3. How can I determine if a set of vectors spans a subspace?

A set of vectors spans a subspace if every vector in the subspace can be written as a linear combination of the given vectors. This can be checked by setting up a system of equations and solving for the coefficients of the linear combination.

4. What is the dimension of a subspace?

The dimension of a subspace is the number of linearly independent vectors needed to span the subspace. It is also equal to the number of elements in a basis for the subspace.

5. Can a subspace have an infinite number of dimensions?

No, a subspace can only have a finite number of dimensions. This is because a subspace is a subset of a vector space, which is a finite dimensional object.

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