00:01
We have to find the rank of matrix a equal to matrix 1 minus 1 2 minus 3, 4102 0 314 and 0102.
00:18
So in order to find the rank of this matrix we need to do the column operations and row operations.
00:25
First i'm doing some column operations that c2 changes to c2.
00:32
2 plus c1 then c3 changes to c3 minus 2c1 and c4 changes to c4 plus 3 c1 then c2 becomes 4 plus 1 5 sorry 1 plus 1 0 plus 1 0 plus 3 3 and 0 plus 1 1 1 so we can write the matrix after doing all this column transformations that is equal to matrix 1 -0 -0 -0 -0 -8 -14 -0 -3 -1 -0 -0 -0 -0 -0 -0 -2 okay now we need to 1 in place of this so here we have one we can interchange these two rows r2 interchange with r4.
01:40
Next operation, then we get the matrix 1 -0 -0 -0 -0 -0 -0 -0 -3 -14 and 0 -5 minus 8 -4.
01:58
Now we need to make these two numbers 0.
02:01
For that, we can do the column operation.
02:14
Before that, we can do one column operation c4 changes to c4 minus 2c2.
02:26
That becomes matrix 1 -0 -0 -1 -0 -0 -0 -0 -0 -0 -0 -0.
02:36
Then c4 minus 2c2 that is 4 minus 6 minus 2 and 4 minus 10 that is minus 10 so we get 0 3 1 minus 8 4 okay, we got this matrix.
03:16
Now, making these two numbers zero, we do the operation, three changes to r3 minus 3 or 2...