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- HI, THIS VIDEO WILL SHOW YOU HOW TO FIND THE INVERSE
OF A MATRIX ON YOUR GRAPHING CALCULATOR.
WE'VE ALREADY SHOWN HOW TO DO IT BY HAND
SO HERE'S A WAY YOU CAN CHECK YOUR ANSWERS.
THE FIRST THING WE NEED TO DO IS JUST ENTER IN THE MATRIX.
SO IF WE PRESS 2nd, MATRIX AND THEN GO OVER TO THE EDIT MENU
BY PRESSING RIGHT TWICE LETS GO AHEAD
AND ENTER IN THE FIRST MATRIX IN MATRIX "A."
SO WE'LL PRESS ENTER AND LET'S SAY IT'S A 2 BY 2
TO START WITH SO WE'LL PRESS 2 ENTER, 2 ENTER
AND LET'S GO AHEAD AND JUST TYPE IN SOME ELEMENTS.
LET'S SAY 4, -3, 7, AND 2, ENTER
AND LET'S GO AHEAD AND ENTER IN A 3 BY 3 INTO MATRIX B.
SO 2nd MATRIX, RIGHT ARROW OVER TO EDIT
AND NOW WE'LL SCROLL DOWN TO MATRIX B AND PRESS ENTER.
AND WE'RE GOING TO USE A 3 BY 3 MATRIX
AND IT'S ALREADY SET UP AS A 3 BY 3
SO WE'LL JUST PRESS ENTER, ENTER,
AND THEN WE'LL GO AHEAD AND ENTER IN THE ELEMENTS.
LET'S JUST GO AHEAD AND ENTER IN 1, ENTER, 2,
ENTER, 3, ENTER, -2, ENTER, 6, ENTER, -1, ENTER
AND THEN THE LAST ROW IS GOING TO BE 4, ENTER, 1,
ENTER, AND 9, ENTER.
OKAY, SO ONCE WE'VE ENTERED IN THE MATRICES
WE JUST HAVE TO GO BACK TO THE HOME SCREEN
BY PRESSING 2nd MODE FOR THE QUIT OPTION
AND THEN WE'RE GOING TO SELECT THE MATRIX.
SO LET'S GO AHEAD AND SELECT MATRIX "A",
2nd MATRIX, PRESS ENTER
AND THEN TO FIND THE INVERSE OF THIS MATRIX
WE JUST HAVE TO PRESS X TO THE -1 FOR THE INVERSE.
SO WE PRESS THIS KEY HERE AND THEN WE JUST PRESS ENTER.
NOTICE THIS ONE IS IN DECIMAL NOTATION.
WE CAN EASILY CONVERT THIS TO FRACTION NOTATION
BY PRESSING MATH, ENTER, ENTER,
AND THERE IS THE INVERSE OF THAT 2 BY 2 MATRIX
THAT WE ENTERED AND LET'S GO AHEAD
AND DO THE SAME FOR THE 3 BY 3.
SO NOW WE'LL SELECT MATRIX B,
2nd, MATRIX SELECT MATRIX B AND WE'LL DO THE SAME THING.
JUST PRESS THE INVERSE KEY HERE AND PRESS ENTER
AND AGAIN THIS ONE IS IN DECIMAL NOTATION
BUT IF WE REALLY WANT FRACTIONAL NOTATION
WE JUST NEED TO PRESS MATH, ENTER, ENTER,
AND THERE IT IS IN FRACTION NOTATION.
NOW NOTICE ON THE RIGHT WE HAVE THREE DOTS
MEANING THERE'S MORE INFORMATION OVER HERE ON THE RIGHT
SO WE CAN PRESS THE RIGHT ARROW AND WE CAN SCROLL OVER THERE
TO SEE THE ENTIRE MATRIX.
OKAY, I HOPE YOU FOUND THIS VIDEO HELPFUL.
AGAIN, THIS IS A NICE WAY TO CHECK YOUR WORK
AFTER YOU HAVE FOUND INVERSE MATRICES BY HAND.
THANK YOU AND HAVE A GOOD DAY.