# Example 12 - Chapter 14 Class 11 Mathematical Reasoning

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Example 12 Given below are two pairs of statements. Combine these two statements using if and only if . (i) p: If a rectangle is a square, then all its four sides are equal. q: If all the four sides of a rectangle are equal, then the rectangle is a square. A rectangle is a square if and only if all its four sides are equal. Or All four sides of rectangle are equal if and only if it is a square Example 12 Given below are two pairs of statements. Combine these two statements using if and only if . (ii) p: If the sum of digits of a number is divisible by 3, then the number is divisible by 3. q: If a number is divisible by 3, then the sum of its digits is divisible by 3. A number is divisible by 3 if and only if the sum of its digits is divisible by 3. Or The sum of digits of a number is divisible by 3 ; if and only if a number is divisible by 3

Chapter 14 Class 11 Mathematical Reasoning

Concept wise

- Statements
- Writing negation of statements
- Negation - Checking if true or not
- Finding Compound Statement
- Words 'And' & 'Or'
- Inclusive and exclusive or
- Quantifiers
- Contrapositive and converse
- If then
- If and only if
- Proving not true/false (by giving counter examples)
- Proving True - If and only if
- Proving True - By Contrapositive
- Proving True - By Contradiction
- Necessary and sufficient condition

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.