Difference between revisions of "Matrix Algebra and Matrix Multiplication"
Line 44: | Line 44: | ||
===Multiplying matrices by scalars=== | ===Multiplying matrices by scalars=== | ||
+ | When multiplying a matrix by a scalar (or number), all we need to do is multiply each entry of the matrix by the scalar. For example: | ||
+ | <math>3\begin{bmatrix} | ||
+ | 1 & 2 & 3\\ | ||
+ | 0 & 1 & 2\\ | ||
+ | 0 & 0 & 1 | ||
+ | \end{bmatrix} = | ||
+ | 3 & 6 & 9\\ | ||
+ | 0 & 3 & 6\\ | ||
+ | 0 & 0 & 3 | ||
+ | \end{bmatrix} | ||
+ | </math> | ||
+ | |||
+ | |||
+ | <math>-\frac{1}{2}\begin{bmatrix} | ||
+ | 2 & -4 & 8\\ | ||
+ | -2 & 1 & -6\\ | ||
+ | 0 & 0 & 7 | ||
+ | \end{bmatrix} = | ||
+ | -1 & 2 & -4\\ | ||
+ | 1 & -\frac{1}{2} & 3\\ | ||
+ | 0 & 0 & -\frac{7}{2} | ||
+ | \end{bmatrix} | ||
+ | </math> | ||
===Multiplying matrices=== | ===Multiplying matrices=== |
Revision as of 11:32, 17 September 2021
Contents
Matrix Operations
Adding and subtracting matrices
In order to add or subtract two matrices, they must be of the same dimension; that is, the two matrices must have the same number of rows and the same number of columns. To add two matrices together, we simply need to add every entry in one matrix to the entry in the same row and same column in the other matrix. For example:
Multiplying matrices by scalars
When multiplying a matrix by a scalar (or number), all we need to do is multiply each entry of the matrix by the scalar. For example:
Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 3\begin{bmatrix} 1 & 2 & 3\\ 0 & 1 & 2\\ 0 & 0 & 1 \end{bmatrix} = 3 & 6 & 9\\ 0 & 3 & 6\\ 0 & 0 & 3 \end{bmatrix} }
Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle -\frac{1}{2}\begin{bmatrix} 2 & -4 & 8\\ -2 & 1 & -6\\ 0 & 0 & 7 \end{bmatrix} = -1 & 2 & -4\\ 1 & -\frac{1}{2} & 3\\ 0 & 0 & -\frac{7}{2} \end{bmatrix} }
Multiplying matrices
Resources
- Matrix Addition and Subtraction, Khan Academy
- Multiplying Matrices by Scalars, Khan Academy
- Matrix Multiplication, Khan Academy