# Using Symbolab

TLDRThis video demonstrates how to find the inverse of a matrix using Symbolab's matrix calculator, which is especially useful for 3x3 or larger matrices due to the complexity of manual row operations. The process involves augmenting the matrix with the identity matrix and using Symbolab to perform the row reduction. The video illustrates that if the resulting left matrix is not the identity, the original matrix is not invertible, as shown with the example matrix 1 2 3 4 5 6 7 8 9. The contradiction in the reduced row echelon form confirms the impossibility of finding an inverse for this matrix.

### Takeaways

- π The video discusses the method of finding the inverse of a matrix, which can be messy, especially for 3x3 or larger matrices.
- π It suggests using Symbolab, an online matrix calculator, for finding the inverse of matrices to avoid complex manual calculations.
- π The script demonstrates how to use Symbolab by selecting the appropriate matrix size, in this case, a 3x6 matrix for a 3x3 matrix inverse.
- π¨βπ« The presenter types in a 3x3 matrix and shows the process of augmenting it with an identity matrix and then reducing it to find the inverse.
- β When the process is completed correctly, the left side of the augmented matrix should show the identity matrix, indicating the successful finding of the inverse.
- π« The script also shows what happens when the original matrix is not invertible, as it does not lead to the identity matrix on the left side after reduction.
- π’ It explains that a non-invertible matrix, such as the one with elements 1 2 3 4 5 6 7 8 9, cannot have an inverse because multiplying it by any matrix will not result in the identity matrix.
- π€ The video uses the concept of reduced row echelon form (RREF) to illustrate the process of finding or determining the non-existence of a matrix inverse.
- π The script points out that if the leading ones in the RREF do not align correctly from top left to bottom right, the matrix is not invertible.
- π It highlights the contradiction that arises when trying to solve for a matrix inverse that does not exist, using the example of the first column of the inverse matrix.
- π The video concludes by emphasizing the usefulness of Symbolab for performing row operations and finding matrix inverses, which would otherwise be cumbersome to do by hand.

### Q & A

### What is the primary method discussed in the transcript for finding the inverse of a matrix?

-The primary method discussed is using an online matrix calculator called Symbolab to find the inverse of a matrix through row operations.

### Why is the manual method for finding the inverse of a 3x3 matrix considered messy?

-The manual method is considered messy because it involves a lot of row operations, which can be time-consuming and prone to errors.

### What is the minimum size of the matrix needed to find the inverse of a 3x3 matrix using Symbolab?

-A minimum size of 3x6 is needed because it involves augmenting the 3x3 matrix with a 3x3 identity matrix.

### How does Symbolab assist in finding the inverse of a matrix?

-Symbolab assists by performing the row operations automatically to reduce the augmented matrix to its reduced row-echelon form, which helps in identifying the inverse matrix.

### What does the appearance of the identity matrix on the left side of the reduced matrix indicate?

-The appearance of the identity matrix on the left side indicates that the original matrix is invertible and has been successfully reduced to its reduced row-echelon form.

### What does it mean if the left side of the reduced matrix is not the identity matrix?

-If the left side is not the identity matrix, it means the original matrix is not invertible, as it does not have an inverse that would result in the identity matrix upon multiplication.

### How can you determine if a matrix is not invertible by looking at the reduced row-echelon form?

-You can determine if a matrix is not invertible by checking if the left side of the reduced row-echelon form is not the identity matrix, indicating a contradiction in the system of equations.

### What is the significance of the contradiction mentioned in the transcript?

-The contradiction signifies an impossibility in the system of equations, meaning there is no solution and thus the matrix does not have an inverse.

### Why is it impossible for the matrix A multiplied by a vector B to result in the identity matrix if the matrix A is not invertible?

-It is impossible because the matrix A, when multiplied by any vector B, cannot satisfy the condition of an identity matrix multiplication, which requires a unique inverse that does not exist in this case.

### What is the final message conveyed in the video regarding the use of Symbolab for finding matrix inverses?

-The final message is that using Symbolab to find matrix inverses through row operations is a practical and efficient method, especially when doing so by hand would be messy and error-prone.

### Outlines

### π§© Finding the Inverse of a Matrix with Symbolab

The paragraph discusses the complexity of finding the inverse of a matrix, especially for 3x3 or larger matrices, and introduces the use of Symbolab for this purpose. It explains the process of using Symbolab's matrix calculator to input a 3x3 matrix and an augmented identity matrix, then using row operations to reduce the matrix to its reduced row echelon form. The paragraph demonstrates the process by inputting a specific matrix, changing one of its elements to see the effect on invertibility, and explaining the outcome of the operation.

### Mindmap

### Keywords

### π‘Inverse of a matrix

### π‘Row operations

### π‘Symbolab

### π‘Matrix calculator

### π‘3x3 matrix

### π‘Identity matrix

### π‘Reduced row echelon form

### π‘Non-invertible matrix

### π‘Matrix multiplication

### π‘System of equations

### Highlights

Solving for the inverse of a matrix can be messy, especially for 3x3 or larger matrices.

For 2x2 matrices, finding the inverse is manageable, but larger matrices require a calculator.

Symbolab Matrix Calculator is introduced as a tool for finding matrix inverses.

To find the inverse of a 3x3 matrix, a 3x6 matrix is needed.

The process involves augmenting the matrix with an identity matrix and then reducing it.

The identity matrix on the left side indicates the matrix is in reduced row echelon form.

The matrix on the right side is the inverse of the original matrix if the left side is the identity matrix.

If the left side is not the identity matrix, the original matrix is not invertible.

Multiplying the original matrix by its inverse should result in the identity matrix.

Attempting to find the inverse of a non-invertible matrix leads to a contradiction.

The reduced row echelon form of a 3x4 matrix can help determine if the matrix is invertible.

A contradiction in the reduced row echelon form indicates the matrix is not invertible.

The impossibility of the matrix equation a * b = I where I is the identity matrix signifies non-invertibility.

Symbolab automates the row operations, simplifying the process of finding matrix inverses.

The video demonstrates the practical application of Symbolab for matrix inversion.

The importance of correctly identifying when a matrix is not invertible is emphasized.

The video concludes by summarizing the process and the utility of Symbolab for matrix operations.