Proving the Frobenius Norm Identity for Matrices: A Step-by-Step Guide

In summary, the Frobenius Norm in Linear Algebra is a matrix norm that measures the magnitude of a matrix by taking the square root of the sum of the squares of all its elements. It is calculated using a mathematical formula and has various properties, such as being non-negative and following the triangle inequality. The significance of the Frobenius Norm lies in its ability to measure error and determine the condition number of a matrix, making it useful in various applications such as data analysis and machine learning.
  • #1
iwan89
27
0

Homework Statement



Prove ∥A∥F =√trace(ATA), for all A ∈ R m×n

Where T= transpose



Homework Equations





The Attempt at a Solution


I tried and i just can prove it by using numerical method. Is there anyway to prove the equation in a correct way?
 
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  • #2
The product AT A worked out gives the sum of all entries squared.
 
  • #3
Can you give me a head start? :( I am in total lost :(
 
  • #4
iwan89 said:
Can you give me a head start? :( I am in total lost :(

Write trace(AA^T) out in index notation.
 

1. What is the Frobenius Norm in Linear Algebra?

The Frobenius Norm in Linear Algebra is a type of matrix norm that measures the magnitude of a matrix. It is also known as the Euclidean Norm and is defined as the square root of the sum of the squares of all the elements in the matrix.

2. How is the Frobenius Norm calculated?

The Frobenius Norm is calculated by taking the square root of the sum of the squares of all the elements in the matrix. Mathematically, it can be represented as ||A||F = √(∑i,j |ai,j|2), where A is the matrix and ai,j is the element in the i-th row and j-th column.

3. What is the significance of the Frobenius Norm in Linear Algebra?

The Frobenius Norm is an important concept in Linear Algebra as it helps in measuring the error or distance between two matrices. It is also useful in determining the condition number of a matrix, which is an indicator of how sensitive the solution of a linear system is to small changes in the input data.

4. What are the properties of the Frobenius Norm?

The Frobenius Norm has several properties, such as being non-negative, being equal to zero if and only if the matrix is a zero matrix, and being invariant under orthogonal transformations. It also follows the triangle inequality, which states that ||A+B||F ≤ ||A||F + ||B||F for any two matrices A and B.

5. How is the Frobenius Norm used in applications?

The Frobenius Norm is commonly used in applications such as data analysis, image processing, and machine learning. It is especially useful in measuring the error or difference between two matrices, which is important in finding the best fit or optimal solution in these applications. It is also used in various algorithms, such as principal component analysis and singular value decomposition.

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