Subspace in R^4: Investigating (2x+3y, x, 0, 1) as a Potential Subspace

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In summary, the conversation discusses whether a given subset is a subspace of R^4. The criteria for a subspace include having an additive identity, closure under vector addition, and closure under scalar multiplication. The subset is being evaluated based on these criteria by checking for an additive identity, whether the sum of two vectors from the subset is still in the subset, and whether the scalar multiple of any vector in the subset is still in the subset. The focus is on the fourth component in a scalar product.
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Homework Statement



Is this a subspace of R^4, (2x+3y, x, 0 , 1) . Give reasons

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The Attempt at a Solution



I am completely stuck at this one
 
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  • #2
A subset U of V is a subspace of V if it satisfies the properties needed to be a vector space: additive identity; closure under vector addition; closure under scalar multiplication.

Check that your given subset satisfies the properties.

a) Is there an additive identity from your set for R^4?

b) If you take two vectors from your given space, a and b, is a+b still in your set?

c) Is the scalar multiple of any vector in your set still in the set?
 
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  • #3
You might want to look particularly at the fourth component in a scalar product such as 2v.
 

FAQ: Subspace in R^4: Investigating (2x+3y, x, 0, 1) as a Potential Subspace

Question 1: What is a subspace?

A subspace is a subset of a vector space that satisfies three properties: closure under addition, closure under scalar multiplication, and contains the zero vector.

Question 2: How do I determine if a set is a subspace of R^4?

To determine if a set is a subspace of R^4, you must check if it satisfies the three properties of a subspace: closure under addition, closure under scalar multiplication, and contains the zero vector. If all three properties are satisfied, then the set is a subspace of R^4.

Question 3: Can a subspace of R^4 have more than four dimensions?

No, a subspace of R^4 can only have a maximum of four dimensions since R^4 is a four-dimensional vector space. Any set with more than four dimensions cannot be a subset of R^4.

Question 4: Is the empty set considered a subspace of R^4?

Yes, the empty set is considered a subspace of R^4 since it satisfies the three properties of a subspace. It is closed under addition and scalar multiplication, and it contains the zero vector.

Question 5: Can a line or a plane be a subspace of R^4?

Yes, a line or a plane can be a subspace of R^4 as long as it satisfies the three properties of a subspace. For example, the x-axis or the xy-plane can be considered subspaces of R^4.

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