# NCERT Class 12-Mathematics: Exemplar Chapter –3 Matrices Part 4

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## Objective Type Questions

### Choose the Correct Answer from the Given Four Options in Examples 9 to 12

**Question 9:**

If A and B are square matrices of the same order, then is equal to

(A)

(B)

(C)

(D)

**Answer:**

(C) Is correct answer.

**Question 10:**

If

(A) Only AB is defined

(B) Only BA is defined

(C) AB and BA both are defined

(D) AB and BA both are not defined.

**Answer:**

(C) Is correct answer.

Let Both AB and BA are defined.

**Question 11:**

The matrix is a

(A) Scalar matrix

(B) Diagonal matrix

(C) Unit matrix

(D) Square matrix

**Answer:**

(D) Is correct answer.

**Question 12:**

If A and B are symmetric matrices of the same order, then is a

(A) Skew symmetric matrix

(B) Null matrix

(C) Symmetric matrix

(D) None of these

**Answer:**

(A) Is correct answer since

### Fill in the Blanks in Each of the Examples 13 to 15

**Question 13:**

If A and B are two skew symmetric matrices of same order, then AB is symmetric matrix if ________.

**Answer:**

.

**Question 14:**

If A and B are matrices of same order, then is equal to ________.

**Answer:**

.

**Question 15:**

Addition of matrices is defined if order of the matrices is ________

**Answer:**

Same.

### State Whether the Statements in Each of the Examples 16 to 19 is True or False

**Question 16:**

If two matrices A and B are of the same order, then .

**Answer: True**

**Question 17:**

Matrix subtraction is associative

**Answer: False**

**Question 18:**

For the non-singular matrix .

**Answer: True**

**Question 19:**

for any three matrices of same order.

**Answer: False**