
Then Choose the correct options:
Solution
Note that the range R(A) is the column space of A. Thus,
R(A) = Span{A1,A2,A3,A4},
where Ai is the i-th column vector of A.
We reduce the matrix A by elementary row operations as follows.
We have

The first and the third column contain the leading 1’s.
Thus, the set {A1,A3} is a basis of the range R(A), which consists of the first and the third column vectors of A
we know that {A1,A3}is a basis of the range of A
Hence the dimension of the range is 2
Thus the rank of A, which is the dimension of the range R(A), is 2
Recall the rank-nullity theorem. Since A is a 3×4 matrix, we have
rank of A+nullity of A= 4.
Since we know that the rank of A is 2, it follows from the rank-nullity theorem that the nullity of A is 2