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Last updated at May 29, 2018 by Teachoo

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Example 3 Write the negation of the following statements and check whether the resulting statements are true, (i)Australia is a continent. Negation of given statement Australia is a not continent. We know that Australia is a Continent Hence the resulting statement is false. Example 3 Write the negation of the following statements and check whether the resulting statements are true, (ii) There does not exist a quadrilateral which has all its sides equal. Negation of given statement There exists a quadrilateral which has all sides equal. We know that square is a quadrilateral having all sides are equal. Hence resulting statement is false. Example 3 Write the negation of the following statements and check whether the resulting statements are true, (iii) Every natural number is greater than 0. Negation of given statement Every natural number is not greater than 0. We know that every natural number is greater than 0. Hence resulting statement is false. Example 3 Write the negation of the following statements and check whether the resulting statements are true, (iv) The sum of 3 and 4 is 9. Negation of given statement The sum of 3 and 4 is not 9. We know that the sum of 3 and 4 is 7. Hence resulting statement is true.

Negation - Checking if true or not

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.