# Relation of null space to linear independence of columns | Summary and Q&A

67.4K views
July 1, 2016
by
Relation of null space to linear independence of columns

## TL;DR

The video explains the relationship between the linear independence of the column vectors of a matrix and the null space of that matrix.

## Key Insights

• 👾 A matrix with linearly independent column vectors will have a null space consisting only of the zero vector.
• 😫 The null space of a matrix is the set of all vectors that, when multiplied by the matrix, result in the zero vector.
• 👷 Linear independence of column vectors means that none of the vectors can be constructed by linear combinations of the others.
• 👾 The ability to find a non-zero solution in the null space of a matrix indicates that the column vectors are linearly dependent.
• 👾 The concept of linear independence and the null space of a matrix are fundamental in linear algebra.
• 👾 Matrix-vector multiplication can help determine the relationship between the null space and linear independence of column vectors.
• 👾 The null space of a matrix is only one of the many applications of linear algebra.

## Transcript

• [Voiceover] So I have the matrix A over here, and A has m rows and n columns, so we could call this an m by n matrix. And what I want to do in this video, is relate the linear independence, or linear dependence, of the column vectors of A, to the null space of A. So what, first of all what I am talking about as column vectors? Well as you can see... Read More

### Q: What is the relationship between the column vectors of a matrix and the null space of that matrix?

The column vectors of a matrix can be viewed as m-dimensional vectors. The null space of a matrix consists of all vectors that, when multiplied by the matrix, result in the zero vector.

### Q: How can the linear independence of the column vectors be determined?

The column vectors of a matrix are linearly independent if and only if the only solution to the equation involving the matrix and a vector from the null space is for all components of the vector to be zero.

### Q: What does it mean for a matrix to have a null space that only contains the zero vector?

If the null space of a matrix only contains the zero vector, it means that the column vectors of the matrix are linearly independent.

### Q: Can a matrix have both linearly independent and linearly dependent column vectors?

No, if a matrix has linearly independent column vectors, its null space must only contain the zero vector. On the other hand, if the null space of a matrix contains only the zero vector, it means that the column vectors are linearly independent.

## Summary & Key Takeaways

• The video discusses how the column vectors of a matrix can be viewed as m-dimensional vectors.

• The null space of a matrix is the set of all vectors that, when multiplied by the matrix, result in the zero vector.

• The video shows that if the column vectors of a matrix are linearly independent, the null space of the matrix consists only of the zero vector.