key term - Row Echelon Form

Definition

Row echelon form is a specific arrangement of the rows in a matrix where the leading entry (the first nonzero entry from the left) in each non-zero row is 1, and is the only nonzero entry in its column. This form is particularly useful in solving systems of linear equations and analyzing the properties of matrices.

5 Must Know Facts For Your Next Test

1. Row echelon form is used to solve systems of linear equations with three variables by converting the augmented matrix into row echelon form.
2. The row echelon form of a matrix can be obtained by performing a sequence of elementary row operations on the matrix.
3. The number of leading 1's in the row echelon form of a matrix is equal to the rank of the matrix.
4. Reduced row echelon form is a more refined version of row echelon form where all leading entries are 1 and all other entries in the leading column are 0.
5. Row echelon form is also used in matrix inverse calculations and to determine the independence of the columns or rows of a matrix.

Review Questions

• Explain how row echelon form is used to solve systems of linear equations with three variables.
  • To solve a system of linear equations with three variables using row echelon form, the augmented matrix of the system is first constructed. Then, a series of elementary row operations, such as row swapping, row scaling, and row addition, are performed on the augmented matrix to convert it into row echelon form. The resulting row echelon form of the augmented matrix can then be used to determine the values of the variables that satisfy the system of equations.
• Describe the relationship between the row echelon form of a matrix and the rank of the matrix.
  • The number of leading 1's in the row echelon form of a matrix is equal to the rank of the matrix. The rank of a matrix represents the number of linearly independent rows or columns in the matrix. This relationship is important because it allows the rank of a matrix to be easily determined by examining its row echelon form, which can provide valuable insights into the properties of the matrix and the system of linear equations it represents.
• Analyze how the process of obtaining the row echelon form of a matrix is used in the context of solving systems of equations using matrices.
  • When solving systems of linear equations using matrices, the process of obtaining the row echelon form of the augmented matrix is a crucial step. By performing elementary row operations on the augmented matrix, the system of equations is transformed into an equivalent system that is easier to solve. The row echelon form of the augmented matrix reveals the number of linearly independent equations, the number of free variables, and the unique or infinite solutions to the system of equations. This information is essential for understanding the properties of the system and determining the appropriate solution methods.

Related terms

Reduced Row Echelon Form:

A more refined version of row echelon form where all leading entries are 1 and all other entries in the leading column are 0.

Elementary Row Operations:

Basic operations performed on the rows of a matrix, such as row swapping, row scaling, and row addition, that preserve the solution set of a system of linear equations.

Rank of a Matrix:

The number of linearly independent rows or columns in a matrix, which is equal to the number of leading 1's in the row echelon form of the matrix.