ch4 matrices - how to use the calculator
TRANSCRIPT
Chapter 4 Calculator Work – Matrices Entering a Matrix on your TI-‐84 graphing calculator: Enter in the following matrix: −3 4 02 −5 10 2 3
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1. From the home screen go to the matrix screen and edit matrix A
2. Enter in the dimensions of the matrix: (rows x columns)
Press
When you arrow over Edit will be highlighted. Then press enter
This screen will appear
At this screen, enter in the matrix
dimensions
When this screen appears, enter in the matrix
elements
3. Enter in the numbers of the matrix:
To evaluate the determinant: Once the matrix is entered quit to go to the home screen. Go back to the matrix screen then arrow over to MATH
Remember to press enter to move to the next space. The elements are entered from left to right.
The key combination starts here after you
enter in the dimensions.
Enter Key Combination
Home Screen
Press enter to select 1:det( which stands for determinant. Go back to the matrix screen. Press enter to select matrix A This screen will appear. Press enter again. This will give you the answer for finding the determinant.
To evaluate the inverse: Once the matrix is entered Quit to go to the home screen. Go back to the matrix screen then press enter to select matrix A.
Answer
This screen will appear after you press enter
Matrix Screen
This screen will appear. Without changing screens, press the inverse key. A -‐1 will appear in the superscript. Press enter. After you press enter the following screen will appear.
Inverse Key
To change from decimals to fractions select the Math Key The following screen will appear. Make sure 1:Frac is highlighted. Then press enter. (Frac stands for fraction) After pressing enter, the following screen will appear. Press enter again. (Ans stands for Previous Answer)
Once you press enter, the decimals will change to fractions. The following is the Inverse Matrix.
Solving a system of equations using the calculator Solve the following system:
5 5 10
2
2 3 3
x y zx y zx y z
+ + = −
+ + =
+ + = −
⎧⎪⎨⎪⎩
Write the system as an augmented matrix 1 5 5 −10
1 1 1 21 2 3 −3
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Enter in the matrix in the Edit Screen in the Matrix Screen Quit and go to the home screen.
Answer
Then go to the Matrix Math Screen. Arrow down to B:rref( Press enter. This screen will appear. Next go the Matrix Screen and select Matrix A by pressing enter This screen will appear. Press Enter
Arrow over to the Math Menu
Make sure this is highlighted. Press Enter
This screen appears with the final answer. The answer in the first row, fourth column is x. The answer in the second row, fourth column is y. The answer in the third row, fourth column is z. Answer: (5, -‐1, -‐2) *If answer appears that looks like this it is a No Solution Answer *If answer appears that looks like this, it is Infinitely many Solutions
If there is a number other zero here, then it is a No Solution
Answer
If a row shows as all zeros, there is infinitely many
solutions