Is [3, -8, 1], [6, 2, -5] a Basis for R3?

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SUMMARY

The vectors [3, -8, 1] and [6, 2, -5] do not form a basis for R3, as they do not span the entire three-dimensional space. However, they are linearly independent and span R2, which is defined as a plane within R3. To establish linear independence, one must verify that neither vector is a scalar multiple of the other and that neither is the zero vector. Thus, these two vectors can be considered a basis for a plane in R3.

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Homework Statement


Determine whether the set is a basis for R3.

[3, -8, 1] , [6, 2, -5]



The Attempt at a Solution



I know it does not span R3, but the book says it is a basis for a plane in R3. How is it a plane?
 
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It doesn't span R3, but it does span R2, which you can think of as a plane in R3.
 
You first have to prove that the 2 vectors are linearly independent. To do that, recall the definition of linear dependence for 2 vectors. What does it mean for 2 vectors to be linearly dependent? If it doesn't satisfy that definition, and if none of the vectors is the zero vector, then you would have 2 linearly independent vectors.

If you have only 1 linearly independent vector, then the linear span of that vector would be a line.

The linear span of 2 linearly independent vectors is a plane in R^n.
 

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