00:02
When we want to examine the product of two matrices to see if they'll inverse to each other, this basically means that if our product is an identity matrix, then we know that they are the inverse to each other.
00:15
They're multiplying across the row and down the column of the right matrix, we see that 1 times 3 is 3, minus 1 times minus 2 is positive 3.
00:37
Minus 1 times minus 2 is positive 2 and then 1 times minus 4 is minus 4 and then 1 times 3 is 3 minus 1 times minus 2 is positive 2 and 1 times minus 5 is minus 5 and the final top right column 1 times minus 1 is minus 1 and and 1 times 2 is positive 2.
01:13
The middle row times the first column, 0 times 3 is 0, 2 times minus 2 is negative 4, minus 1 times minus 4 is plus 4.
01:33
The middle row times middle column 0 times 3 is 0.
01:40
2 times minus 2 is minus 4 and minus 1 and minus 1 times.
01:45
Minus 5 is plus 5 the right column times the middle row 0 times minus 1 is 0 2 times 1 is plus 2 minus 1 times 2 is negative 2 bottom left we have 2 times 3 times 2 is 6 3 times negative 2 is plus 6 and 0 times minus 4 is 0 so the bottom middle, two times three is six, three times minus two is negative six again, and zero times minus five is just zero.
02:31
Bottom right, we have zero, no, two times minus one is minus two, three times one is plus three, and zero times two is zero...