Basis for null space, row space, dimension

In summary, the basis for the row space of the given matrix is the set of nonzero rows after reducing it to row echelon form. The basis for the null space can be found by setting Ax = 0 and solving for [A 0] in parametric form. The dimensions of the row space and null space can be found using the equation dim RS + dim NS = # of columns.
  • #1
Maxwhale
35
0

Homework Statement


What are

the basis for the row space and null space for the following matrix? Find the dimension of RS, dim of NS.

[1 -2 4 1]
[3 1 -3 -1]
[5 -3 5 1]


Homework Equations



dim RS + dim NS = # of columns

The Attempt at a Solution



I reduced the matrix into row echelon form and tried to determine everything, but in vain.
 
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  • #2
Come on, this is a pretty fundamental question. If you want to find the row space, you are going to want to row reduce the matrix and use all the nonzero rows as a basis.

To find the null space, set Ax = 0 and solve [ A 0] and right the solution in parametric form. Take the vectors you have in parametric form as your basis.
 

What is the basis for null space?

The basis for null space is a set of vectors that span the null space of a matrix. These vectors are linearly independent and can be used to represent all solutions to the homogeneous equation Ax = 0, where A is the original matrix.

What is the basis for row space?

The basis for row space is a set of vectors that span the row space of a matrix. These vectors are linearly independent and can be used to represent all possible linear combinations of the rows of the matrix.

How is the dimension of null space determined?

The dimension of null space is determined by finding the number of linearly independent vectors in the basis for the null space. This can be done by reducing the matrix to reduced row echelon form and counting the number of free variables.

Can the dimension of row space be greater than the number of rows in a matrix?

No, the dimension of row space cannot be greater than the number of rows in a matrix. This is because the row space is spanned by the rows of the matrix, and the maximum number of linearly independent rows in a matrix is equal to the number of rows in the matrix.

What is the relationship between the dimension of null space and row space?

The dimension of null space and row space are related by the rank-nullity theorem, which states that the dimension of null space plus the dimension of row space is equal to the number of columns in the matrix. In other words, the dimension of null space and row space are complementary.

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