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- WELCOME TO A VIDEO THAT WILL SHOW
YOU HOW TO USE YOUR TI83 OR 84 TO CALCULATE A DETERMINANT.
NOW THERE IS ANOTHER VIDEO THAT SHOWS YOU HOW TO DO IT BY HAND
BUT IF YOU'RE USING DETERMINANTS
TO SOLVE A VARIETY OF APPLICATION PROBLEMS,
LET'S SAY THE AREA OF A TRIANGLE ON THE COORDINATE PLANE
OR MAYBE EVEN CRAMER'S RULE IT IS NICE
TO BE ABLE TO CHECK YOUR DETERMINANTS
SO LET'S GO AHEAD AND SHOW HOW YOU CAN DO THIS.
LET'S SAY YOU WANT TO FIND THE DETERMINANT
OF THESE TWO MATRICES.
WELL THE FIRST THING WE NEED TO DO IS ENTER THESES MATRICES
INTO THE CALCULATOR.
SO IF WE PRESS 2nd, MATRIX, GO OVER TO THE EDIT MENU,
SO RIGHT ARROW TWICE, AND THEN PRESS ENTER FOR MATRIX "A"
IT'S A 2 x 2.
WE JUST ENTER IN THE ELEMENTS SO -8, -3, 9 AND 1.
LET'S GO AHEAD AND ENTER IN MATRIX B AS WELL.
SO WE'LL PRESS 2nd, MATRIX AGAIN, GO OVER TO THE EDIT MENU,
SCROLL DOWN TO MATRIX B AND THEN PRESS ENTER, ENTER
IN 2 x 2 FOR THE DIMENSIONS AND NOW ENTER THE ELEMENTS.
SO 7, 9, 2, AND 4.
OKAY, NOW WE JUST NEED TO GO BACK TO THE HOME SCREEN.
SO WE'LL PRESS 2nd, QUIT AND THEN WE'RE GOING TO PRESS 2nd,
MATRIX AGAIN AND THEN RIGHT ARROW ONCE TO MATH
AND THE FIRST OPTION IS DET AND THAT STANDS FOR DETERMINANT.
SO WE PRESS ENTER.
THIS BRINGS IT BACK TO THE HOME SCREEN
AND THEN WE SELECT MATRIX "A" SO 2nd, MATRIX, MATRIX "A"
IS SELECTED SO WE PRESS ENTER,
CLOSED PARENTHESES AND PRESS ENTER.
THE DETERMINANT OF MATRIX "A" IS EQUAL TO 19,
AND WE CAN DO THE SAME THING FOR MATRIX B.
BUT ONE THING WE CAN DO TO SAVE US SOME TYPING
IS PRESS 2nd, ENTER.
THAT BRINGS UP THE PREVIOUS ENTRY AND THEN WE CAN EDIT THIS.
SO WE CAN SCROLL OVER TO MATRIX "A" AND THEN JUST DELETE IT
AND NOW WE CAN GO BACK AND SELECT MATRIX B.
SO 2nd, MATRIX AND THEN OPTION 2
OR JUST GO AHEAD AND HIGHLIGHT MATRIX B, PRESS ENTER,
CLOSED PARENTHESES, AND PRESS ENTER.
SO THE DETERMINANT OF MATRIX B IS EQUAL TO 10.
NOW WE KNOW IT'S VERY EASY TO CHECK THESE
WE JUST HAVE TO MULTIPLY 7 x 4 THAT WOULD BE 28 - 9 x 2
THAT WOULD BE 28 - 18 WHICH EQUALS 10.
SO TO FIND THE VALUE OF A 2 x 2 DETERMINANT
ON THE GRAPHING CALCULATOR IS NOT A BIG ADVANTAGE
BUT IF YOU WANT TO FIND THE DETERMINANT OF A 3 x 3
THIS OBVIOUSLY TAKES A LITTLE BIT MORE WORK
SO BEING ABLE TO CHECK THAT VALUE IS A NICE FEATURE.
SO LET'S GO AHEAD AND SEE IF WE CAN FIND THE DETERMINANT
OF THIS MATRIX.
SO FIRST WE'LL ENTER THIS INTO MATRIX "A."
SO AGAIN, 2nd, MATRIX, GO OVER TO EDIT, PRESS ENTER.
NOW IT'S A 3 x 3, ENTER THE ELEMENTS
AND GO BACK TO THE HOME SCREEN, 2nd,
QUIT AND THEN JUST TO SHOW IT ONE MORE TIME WE CAN PRESS 2nd,
MATRIX, TO THE MATH MENU,
AND THEN THE FIRST OPTION IS FOR DETERMINANT.
SELECT MATRIX "A," CLOSE THE PARENTHESES
AND THEN PRESS ENTER AND THIS DETERMINATE IS EQUAL TO 18.
SO THIS WOULD BE A BIG TIME SAFER
BECAUSE WE EITHER HAVE TO USE THE DIAGONAL METHOD
OR THE COFACTOR EXPANSION METHOD TO DO THIS BY HAND.
I HOPE YOU FOUND THIS VIDEO HELPFUL.
THANK YOU FOR WATCHING.