Solve Invertible Matrix Problem: Find Equivalent Conditions to "A is Invertible

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In summary, there are several equivalent conditions for a matrix A to be invertible. These include: the determinant of A is not equal to 0, the number of pivot positions is equal to the number of rows or columns in the matrix, the dimension of the kernel is 0, and there are no free variables in the system of linear equations.
  • #1
eyehategod
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I have to write all possible equivalent conditions to "A is invertible," where A is an nxn matrix. can anyone help me out with this question
 
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  • #2
Name one. You aren't trying very hard.
 
  • #3
i don't understand the question
 
  • #4
well you know that A^-1 = 1/det|A| *adj(A)

so for this to exist...det|A| can't be zero...and think of row-echelon form when finding A^-1

in row-echelon form, to get A^-1. how many non-zero rows must it have?How many pivot positions must it have?
 
  • #5
Here's another one. A is invertible if there is a matrix B such that A*B=I. You are way behind. How about a statement in terms of the dimension of the kernel? How about expressing invertability in terms of the solutions to a system of linear equations? There's a lot of ways to express this concept.
 
  • #6
A is also invertible when the determinant does not equal to 0
 

1. What is an invertible matrix?

An invertible matrix, also known as a non-singular matrix, is a square matrix that has a unique solution for its inverse. This means that the matrix can be multiplied by its inverse to get the identity matrix. In other words, an invertible matrix is a matrix that can be "undone" or reversed.

2. Why is it important for a matrix to be invertible?

It is important for a matrix to be invertible because it allows for solving systems of linear equations, as well as many other mathematical operations. Additionally, invertible matrices have many useful properties, such as being able to find determinants and eigenvalues.

3. How can I tell if a matrix is invertible?

A matrix is invertible if its determinant is non-zero. This means that the matrix has a unique solution for its inverse. Alternatively, you can also check if the matrix has linearly independent columns or rows, as this is another equivalent condition for invertibility.

4. What are the equivalent conditions for a matrix to be invertible?

Aside from having a non-zero determinant and linearly independent columns or rows, there are other equivalent conditions for a matrix to be invertible. These include having a nonzero eigenvalue, having full rank, and being nonsingular.

5. How can I find the inverse of an invertible matrix?

The inverse of an invertible matrix can be found by using various methods, such as Gaussian elimination, Cramer's rule, or using the adjugate matrix. Additionally, many mathematical software and calculators have functions for finding the inverse of a matrix.

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