Do Now: Add or subtract, if possible. 8 5 2 1 6 0 2 5 1 3 1 2 1 7 4 0 3 1 8 0 1 4 1.) 2.)
Jan 17, 2016
Do Now: Add or subtract, if possible.
85
21
602
513
121
740
318
014
1.)
2.)
Academy Algebra II/Trig12.4: Matrix AlgebraHW: p.889 (8, 9, 12, 13, 16, 17, 21)
Scalar Multiplication.
Given , ; find the
following:
85
21A
121
740B
1.) 3A 2.) -B
# columns of the first must be the same as the # rows of the second matrix.
(r x c)(r x c)
Multiplying Matrices
Determine if the matrices can be multiplied.
85
21
602
513
121
740
318
014
1.)
2.)
Operations Using Matrices
40
12AFind the product AB if
21
13B
Operations Using Matrices
085
142AFind AB if
1213
6084
4152
B
Operations Using Matrices
2
1
4
A
Do Now: Find the product AB if
102 B
Academy Algebra II/Trig12.4: Matrix AlgebraHW: p.889 (19, 20, 26 – on calc, 27 – on calc)
Identity Matrix
10
01
An identity matrix has the same number of rows and columns with the 1’s on the main diagonal and zeros for all other cells.
100
010
001
Operations Using Matrices
310
021A
Suppose that
Find by hand and check your answers using your calculator.1.) 2.)
25
64
23
B
3AI 2BI
Input Matrices on TI-89 Calculator:1. Press APPS and select Data/Matrix2. Select 3: New3. Type– 2: Matrix, Folder– Main,
Variable– a4. Press ENTER, ENTER5. Input Matrix A.6. Repeat the steps above for matrix B. 7. Press HOME.8. On the home screen you can
add/subtract/multiply matrices.** If you want to rewrite over a current matrix you can resize it by selecting F6 once you have opened the matrix. **
Input Matrices on TI-83/84 Calculator:1. Press 2nd X-1 to select MATRX2. Arrow over to EDIT3. Select a matrix to edit4. Input the dimensions and # of the
Matrix.5. Repeat the steps above for matrix B. 6. Press 2nd MODE to select QUIT and go
back to home screen.7. On the home screen you can
add/subtract/multiply matrices: go to matrix menu and select matrices from the names menu.