The rank of the matrix | 1 1 | | 0 0 | is A. 4 B. 2 C. 1 D. 0

GATE 2002 · Engineering Mathematics · Rank of Matrix · easy

Answer: Rank = 1

1. Identify row echelon form: The matrix [[1,1],[0,0]] is already in row echelon form. R1 = [1,1] is non-zero; R2 = [0,0] is zero.
2. Count non-zero rows: There is exactly 1 non-zero row (R1). Hence rank = 1.