Gujarat Board GSEB Textbook Solutions Class 11 Maths Chapter 14 Mathematical Reasoning Ex 14.1 Textbook Questions and Answers.

## Gujarat Board Textbook Solutions Class 11 Maths Chapter 14 Mathematical Reasoning Ex 14.1

Question 1.

Which of the following sentences are statements? Give reasons for your answer.

- There are 35 days in a month.
- Mathematics is difficult.
- The sum of 5 and 7 is greater than 10.
- The square of a number is an even number.
- The sides of a quadrilateral have equal lengths.
- Answer their questions.
- The product of (- 1) and 8 is 8.
- The sum of interior angles of a triangle is 180°.
- Today is a windy day.
- All real numbers are complex numbers.

Solution:

1. Statement:

It is false to say that month has 35 days.

2. Sentence:

Mathematics may be difficult for one but may be easy for the other.

3. Statement:

It is true that the sum of 5 and 7 is greater than 10.

4. Sentence:

The square of a number may be even or it may be odd.

e.g., 2^{2} = 4 (even), 3^{2} = 9 (odd).

5. Sentence:

A quadrilateral may have equal lengths as it may be a rhombus or a square or the quadrilateral may have unequal sides.

6. Sentence:

It is an order.

7. Statement:

It is false because product of (- 1) and 8 is not 8.

8. Statement:

It is true that sum of interior angles of a triangle is 180°.

9. Sentence:

It is windy day. Which day it is ?

10. Statement:

It is true that all real numbers are complex number of the form a + i.0.

Question 2.

Give three examples of sentences which are not statements. Give reasons for the answers?

Solution:

- It is a rainy month. Which month is a rainy month? We cannot say which month is rainy.
- She is very beautiful. Who is beautiful?
- You are a brave boy. Who is brave?