00:01
We have given matrix a equal to matrix 1, 2 minus 2, minus 1 3 0 minus 2 1.
00:11
We need to verify that determinant of a inverse equal to 1 by determinant of a.
00:18
For this we need to first find a inverse, then find the determinant of a inverse, then determinant of a inverse, then determinant of a.
00:25
First we can find two determinant of a that is equal to 1 into 3 minus 0 then minus 2 into minus 1 minus 0 minus 2 into okay that is 3 minus 2 into minus 1 that is plus 2 minus 4 5 minus 4 equal to 1 okay determine 8 equal to 1 now we need to find a inverse.
01:09
A inverse.
01:10
We note the formula inverse equal to adjoined of a by determinant of a.
01:17
And where adjoined of a is the transpose of co -factor matrix.
01:24
Co -factor matrix.
01:27
Find co -factor matrix.
01:28
Then take the transpose.
01:30
We get adjoined of a.
01:32
So co -factor is the sine to minus.
01:35
Okay so a 1 1 equal to minus 1 raise 2 1 plus 1 this 1 plus 1 and minor of a 1 1 that is 3 so a 1 1 1 is 3 this is the co -factor of element a 1 1 okay likewise a 1 2 is minus 1 raise 2 1 plus 2 into and the minor of a 1 2 yes minus 1 so we get 1 minus here minus minus minus minus plus then a 1 3 equal to minus 1 raise to 4 into 2 that is 2 a 2 1 is minus 1 raise to 2 plus 1 into minus 2 that is 2 a 2 2 2 is 2 2 2 is minus 2 is minus 2 is minus 2 2 is minus 1 raised to 4 into 1 that is again 1 a2, 3 is minus 1 raised to 5 into minus 2.
02:45
So minus minus 2, that is 2.
02:48
Now a31 is minus 1 raised to 4 into 6.
03:01
That is 6 itself...