Row space of a matrix - question.

In summary, the row space of a matrix is the subspace spanned by its rows, and it is related to the column space through the matrix's rank. The row space is important in understanding matrix properties and can be calculated by finding the linearly independent rows. The row space and null space cannot be equal except in the case of the zero matrix.
  • #1
peripatein
880
0
Hello,

Homework Statement



Could anyone please explain why the row space of a matrix mXn over R is a subspace of R^n, and not of R^m?

Homework Equations





The Attempt at a Solution

 
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  • #2
Because you have m rows and n columns and the rows are your vectors. So you have m vectors each with n components. So you have m vectors in R^n.
 
  • #3
Why are the m vectors in R^n?
 
  • #4
peripatein said:
Why are the m vectors in R^n?

Because they have n components. (1,2,3) is in R^3 because it has 3 components. (1,2,3,4) is in R^4. Etc.
 

What is the row space of a matrix?

The row space of a matrix is the span of the rows of the matrix. It is a subspace of the vector space that the matrix operates on, and it represents all possible linear combinations of the rows of the matrix.

How is the row space related to the column space of a matrix?

The row space and column space of a matrix are related through the rank of the matrix. The rank of a matrix is equal to the dimension of both the row space and the column space. This means that the row space and column space are essentially two different perspectives on the same subspace of the vector space.

What is the importance of the row space in matrix operations?

The row space is important in matrix operations because it helps us understand the fundamental properties of matrices, such as their rank, determinant, and inverse. It also allows us to determine the solutions to systems of linear equations through methods like row reduction.

How can the row space be calculated?

The row space can be calculated by finding the linearly independent rows of a matrix, which form a basis for the row space. This can be done through methods like Gaussian elimination or by finding the reduced row echelon form of the matrix.

Can the row space and null space of a matrix be equal?

No, the row space and null space of a matrix cannot be equal. The row space contains all possible linear combinations of the rows of the matrix, while the null space contains all vectors that are mapped to the zero vector by the matrix. These two subspaces are only equal in the case of the zero matrix, where both the row space and null space are trivial.

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