Problem Set 1 15 . If r is the rank and d is the determinant of the matrix what is r - d ?. Megan Grywalski. Finding the Rank.
The matrix rank is determined by the number of independent rows or columns present in it. A row or a column is considered independent, if it satisfies the below conditions.1. A row/column should have at least one non-zero element for it to be ranked.2. A row/column should not be identical to another row/column.3. A row/column should not be proportional (multiples) of another row/column.4. A row/column should not be a linear combination of another row/column.
1. The first element in the first row should be the leading element i.e. 1.2. The leading element in the columns should be to the right of the previous row's leading element.3. If there are any rows with all zero elements, it should be below the non-zero element rows.4. The leading element should be the only non-zero element in every column.
R Form2-4R1 R3-7R1
Since R3 does not have at least one non-zero element it cannot be ranked. Therefore, the rank is 2.
= - +
= 1(45-48) – 2(36-42) + 3(32-35)
= (-3) + 12 – 9 = 0
So we have r = 2 and d = 0. Therefore, r-d = 2 – 0 = 2