Are Linearly Dependent Vectors Always a Linear Combination?

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Homework Help Overview

The discussion revolves around the concept of linear dependence among vectors, specifically examining the relationship between a set of dependent vectors and their subsets. The original poster presents a question regarding whether a set of linearly dependent vectors implies that any subset of those vectors is also dependent.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the definition of linear dependence and question the implications of having a larger set of dependent vectors. Some participants seek clarification on the original problem statement and the meaning of "definitely dependent."

Discussion Status

The discussion is ongoing, with participants questioning the phrasing of the problem and exploring the implications of linear dependence. Some guidance has been offered regarding the nature of linear combinations within dependent sets, but no consensus has been reached on the interpretation of the problem.

Contextual Notes

There appears to be confusion regarding the original problem statement, with participants suggesting different interpretations. Additionally, examples from different dimensions are being discussed to illustrate points about linear independence and dependence.

Dell
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given the vectors,

v1,v2...vk+1.
show that if v1,v2...vk+1. are dependent then v1,v2...vk+1 are definitely dependent.

can i say that in a series of dependent vectors, at least one must be a linear combination of the others therefore, if v1,v2...vk+1 are dependent, v1,v2...vk+1 must be since it contains the vector which was a linear combination (from the larger series)
 
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What is definitely dependent?
 
Dell,
I think you have written the problem incorrectly. My guess is that this is the problem:

Given the vectors, v1,v2,...,vk+1,
show that if v1,v2,...,vk+1 are linearly dependent, then v1,v2,...,vk are linearly dependent.

To answer your question, yes, in any collection of linearly dependent vectors, it must be the case that one of them is some linear combination of the rest.
 
Mark44 said:
Dell,
I think you have written the problem incorrectly. My guess is that this is the problem:

Given the vectors, v1,v2,...,vk+1,
show that if v1,v2,...,vk+1 are linearly dependent, then v1,v2,...,vk are linearly dependent.

To answer your question, yes, in any collection of linearly dependent vectors, it must be the case that one of them is some linear combination of the rest.
Huh? In R^2 the vectors (1,0), (0,1), (1,1) are linearly dependent, but (1,0) and (0,1) are linearly independent.
 

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