© Zarestky Math 141 Calculator Notes 1.5 The Method of Least Squares To find the least-squares or regression line: STAT and choose 1: Edit Enter the first row/column of data in L1 and the second row/column in L2. STAT then right arrow to the CALC menu. Choose 4: LinReg(ax+b) You are now on the home screen, with “LinReg(ax+b)” showing. VARS then right arrow to Y-VARS, choose 1: Function and 1: Y1. You are now on the home screen, with “LinReg(ax+b) Y1” showing. ENTER Your home screen should now show: LinReg y=ax+b a= [number] b= [number] r2= [number] r= [number] The equation of the line will also be stored as Y1 in the Y = menu. If you are missing the r and r2 values: 2nd CATALOG then D and scroll down to DiagnosticOn. ENTER twice. Repeat the Linear Regression steps.© Zarestky Math 141 Calculator Notes 2.2 Systems of Linear Equations: Unique Solutions 2.3 Systems of Linear Equations: Underdetermined and Overdetermined Systems When you see the directive to go to MATRIX on your calculator, you will press 2nd 1!x. If you have the standard TI-83 version (instead of a TI-83 Plus or any version of a TI-84), when you see directions to go to MATRIX, you need to hit the one button, MATRX To perform Gauss-Jordan elimination when showing all row operations: Enter the matrix: MATRIX and right arrow to EDIT. Select a matrix from the list, most often this will be [A] but it doesn’t matter which one. Enter the size of the matrix: number of rows followed by number of columns. Enter the entries of the matrix. Remember that you are moving across the rows. Press 2nd MODE to QUIT to your home screen. Modify the matrix with a specific row operation: MATRIX and right arrow to MATH. Choose your operation. You may need: C: rowSwap( usage: rowSwap([A], row A, row B) E:*row( usage: *row(value, [A], row) F: *row+( usage: *row+(value, [A], row A, row B) Once you have made your selection, that operation will appear on your home screen. Enter the matrix/values appropriate for the function, separated by commas. (MATRIX and choose 1:[A] for entering the matrix name) Close the parentheses and ENTER. NOTE: When using row operations one after another, you can press 2nd (−) to select ANS in order to refer to the last resulting matrix, instead of storing the new matrix after each separate row operation. To perform Gauss-Jordan elimination without showing all row operations: Enter the matrix: MATRIX and right arrow to EDIT. Select a matrix from the list, most often this will be [A] but it doesn’t matter which one. Enter the size of the matrix: number of rows followed by number of columns.. Enter the entries of the matrix. Remember that you are moving across the rows. Press 2nd MODE to QUIT to your home screen. Modify the matrix with all row operations done in one step: MATRIX and right arrow to MATH. Choose your operation, B: rref( usage: rref([A]) Once you have made your selection, that operation will appear on your home screen. Enter the appropriate matrix. (MATRIX and choose 1:[A]) Close the parentheses and
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