Show that two sets of vectors span the same subspace

In summary, the two sets of vectors {A=(1,1,0), B=(0,0,1)} and {C=(1,1,1), D=(-1,-1,1)} span the same subspace of R3. This is because, through linear combinations, we can see that the vectors (1,1,1) and (-1,-1,1) are also in the space spanned by (1,1,0) and (0,0,1). This is shown by the equation aC+bD=(a,a,a)+(-b,-b,b)=(a-b,a-b,a+b), which is in the same form as aA+bB=(a,a,b).
  • #1
csc2iffy
76
0

Homework Statement


Show that the two sets of vectors
{A=(1,1,0), B=(0,0,1)}
and
{C=(1,1,1), D=(-1,-1,1)}
span the same subspace of R3.


Homework Equations


{A=(1,1,0), B=(0,0,1)}
{C=(1,1,1), D=(-1,-1,1)}

The Attempt at a Solution


aA+bB=(a,a,0)+(0,0,b)=(a,a,b)
aC+bD=(a,a,a)+(-b,-b,b)=(a-b,a-b,a+b)
I am confused because I thought the answers would turn out to be equal.. Is this not the way to do it?
 
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  • #2
Well, take (a-b, a-b, a+b). Now, this equals a(1, 1, 1) + b(-1, -1, 1). Of what form are the vectors (1, 1, 1) and (-1, -1, 1)? Do they look familiar?
 
  • #3
its aC+bD... i don't understand how this is related to aA+bB??
 
  • #4
The two vectors I mentioned are in your space "(a, a, b)". Hence, their linear combination is in that space, too.
 
  • #5
Oh! Thank you! now i see it lol
 

Related to Show that two sets of vectors span the same subspace

1. How do you define a subspace?

A subspace is a subset of a vector space that contains all the elements of the original vector space and satisfies the axioms of a vector space, such as closure under addition and scalar multiplication.

2. What does it mean for two sets of vectors to span the same subspace?

This means that both sets of vectors contain enough elements to create any vector within the subspace. In other words, any vector in the subspace can be written as a linear combination of vectors from either set.

3. How do you show that two sets of vectors span the same subspace?

To show that two sets of vectors span the same subspace, you can demonstrate that any vector in the subspace can be written as a linear combination of vectors from both sets. This can be done by solving a system of equations or by showing that all vectors in the subspace can be expressed as a linear combination of basis vectors from both sets.

4. What is the significance of two sets of vectors spanning the same subspace?

This indicates that the two sets of vectors are equivalent in terms of their ability to define the subspace. It also suggests that the two sets may have similar properties or relationships between their vectors.

5. Can two sets of vectors span multiple subspaces?

Yes, it is possible for two sets of vectors to span multiple subspaces. This can occur if the two sets contain vectors that are linearly independent and can define different subspaces within the same vector space.

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