Can Four Vectors in R3 Have Any Three Linearly Independent?

In summary, in order to prove that there is a set of four vectors in R3, any three of which form a linearly independent set, you can find a set of three linearly independent vectors and then add a fourth vector that is not parallel to any of the others. This will satisfy the requirement for four vectors.
  • #1
nabzy92
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Q: Is there a set of four vectors in R3, any three of which form a linearly independent set? Prove.

Okay so i know what linearly independent is, i have 3 vectors which are linearly independent but I can't find a fourth vector to satisfy the need of the questions like:

vectors: v1 = (0,0,1), v2 = (0,-2,2), v3 = (1,-2,1) these three vectors are linearly independent when you use Guassian Elimination on the matrix:

| 0 0 1 |
| 0 -2 -2 |
| 1 2 1 |

you get all the scalars equal to 0. So this satisfy the part where "any three of which form a linearly independent set" is written but the first part says need 4 vectors.
Any suggestions?
 
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  • #2
Surely come up with a set of three vectors in R3 that form a linearly independent set, right? Now, just add 4th vector that is id to all of them. This is eqivilent to finding a vector that is not parallel to any of the other three.

For example, if we were to ask for a set of 3 vectors in R2 such that any two of them form a linearly independent set, I would say v1=(1,0) v2=(0,1) and v3=(1,1).
 

FAQ: Can Four Vectors in R3 Have Any Three Linearly Independent?

1. What is the definition of linear independence in vectors?

Linear independence in vectors refers to the property of a set of vectors where none of the vectors in the set can be written as a linear combination of the other vectors. This means that no vector in the set is redundant and all contribute unique information to the set.

2. How can I determine if a set of vectors is linearly independent?

A set of vectors is linearly independent if the only solution to the equation c1v1 + c2v2 + ... + cnvn = 0 is c1 = c2 = ... = cn = 0, where c1, c2, ..., cn are scalars and v1, v2, ..., vn are the vectors in the set. This means that the only way to get a zero vector as a linear combination of the set is by setting all the coefficients to zero.

3. Can a set of two vectors be linearly dependent?

Yes, a set of two vectors can be linearly dependent. This happens when one of the vectors is a multiple of the other, or when they lie on the same line. In this case, one of the vectors can be written as a linear combination of the other, making the set linearly dependent.

4. What is the importance of linear independence in vectors?

Linear independence is important in many areas of mathematics and science, including linear algebra, physics, and computer science. It allows for the efficient representation and manipulation of vectors, and is essential in solving systems of linear equations and performing vector operations.

5. How does linear independence relate to the span of a set of vectors?

The span of a set of vectors is the set of all possible linear combinations of those vectors. If a set of vectors is linearly independent, then the span of that set is the entire space in which the vectors exist. If the set is linearly dependent, then the span is a subspace of that space. Therefore, linear independence determines the size and structure of the span of a set of vectors.

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