Determinant Practice Questions Ques3
Question: In a $3 \times 3$ matrix $A$, if the minor of $a_{11}$ is $5$, what is the cofactor of $a_{11}$?
Options:
(A) $5$
(B) $-5$
(C) $10$
(D) $-10$
Show Answer
Answer: A
Explanation:
(A) Correct. The cofactor of $a_{11}$ is $(-1)^{1+1} \times 5 = 5$.
(B) Incorrect. The sign is wrong.
(C) Incorrect. The value is wrong.
(D) Incorrect. Both the sign and value are wrong.
BETA
