Linear Algebra: Orthogonal matrices

In summary, an orthogonal matrix is a square matrix with perpendicular columns and a unit length. Its differences from a regular matrix include the inverse being equal to its transpose and a determinant of either 1 or -1. Applications include linear transformations, data compression, and computer graphics. To check if a matrix is orthogonal, the columns must be perpendicular, have a magnitude of 1, and the inverse must equal the transpose with a determinant of 1 or -1.
  • #1
Niles
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Homework Statement


Hi

A matrix M has an inverse iff it is of full column and row rank, and row rank = column rank. Since any orthogonal matrix has full column rank, does that imply that non-singular matrices are orthogonal as well?

Cheers,
Niles.
 
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  • #2
No, we have that orthogonal => full column rank. But we don't have the converse. There are non-singular matrices which are not orthogonal.
 

Related to Linear Algebra: Orthogonal matrices

1. What is an orthogonal matrix?

An orthogonal matrix is a square matrix in which all the columns are mutually perpendicular to each other and have a unit length. This means that the dot product of any two columns is 0, and the magnitude of each column is 1. Orthogonal matrices are often used in linear algebra for various transformations and calculations.

2. How is an orthogonal matrix different from a regular matrix?

An orthogonal matrix is different from a regular matrix in that its columns are all perpendicular to each other and have a unit length. This means that for an orthogonal matrix A, the inverse of A is equal to its transpose, and the determinant of A is either 1 or -1. In contrast, a regular matrix may have any values for its columns and may not have an inverse or a determinant at all.

3. What are some applications of orthogonal matrices?

Orthogonal matrices have many applications in various fields, including physics, engineering, computer graphics, and statistics. One common use is in linear transformations, where orthogonal matrices can preserve the length and angle of vectors. They are also used in data compression, image processing, and solving systems of linear equations.

4. How are orthogonal matrices used in computer graphics?

In computer graphics, orthogonal matrices are used to perform transformations such as translation, rotation, and scaling on 3D objects. These transformations are important for creating realistic and dynamic graphics in video games, animations, and simulations. Orthogonal matrices are also used in rendering 3D scenes and calculating lighting effects.

5. How can I check if a matrix is orthogonal?

To check if a matrix is orthogonal, you can use the following criteria:

  • The columns of the matrix must be mutually perpendicular, meaning that their dot product is 0.
  • The magnitude of each column must be 1.
  • The inverse of the matrix must be equal to its transpose, or in other words, A-1 = AT.
If these criteria are met, then the matrix is orthogonal. You can also use the determinant of the matrix to check if it is either 1 or -1, as all orthogonal matrices have a determinant of either 1 or -1.

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