Negations
- Intro Lesson3:21
- Lesson: 1a3:12
- Lesson: 1b2:19
- Lesson: 1c1:29
- Lesson: 1d0:29
- Lesson: 1e1:33
- Lesson: 2a2:09
- Lesson: 2b2:40
- Lesson: 2c1:55
- Lesson: 2d2:05
- Lesson: 37:15
- Lesson: 4a6:34
- Lesson: 4b3:42
- Lesson: 4c4:04
Negations
Lessons
The negation of a statement is the opposite of a statement. We denote it with either "not" or the symbol ~. The negation gives the opposite of the truth value. For example,
p: A square is a rectangle
~ p: A square is not a rectangle p is true, so ~p is false.
p: A square is a rectangle
~ p: A square is not a rectangle p is true, so ~p is false.
- IntroductionNegations Overview:a)Definition of Negations and Examples
- 1.Negation of the Statement
Write the negation of each statement:
a)The sun rises from the east.b)1+1=0c)January is the first month of the year.d)The Eiffel Tower is in Japan.e)A square has 7 sides. - 2.Truth Value of a Negation
Write the negation of each statement, and determine the truth value:
a)A snake is a reptile.b)The measure of an acute angle is greater than 90°.c)5+5+5=555d)65 is a fraction. - 3.The symbols represent the following statements
p: A pentagon has 5 sides
q: United States is a city
r: Chairs have four legsWrite a complete sentence in words to show what the symbols means, and find the truth value:
i) ~p
ii) ~q
iii) ~r - 4.Double Negation
Determine the truth value of the statement. Negate it twice, write it in a complete sentence, and determine the new truth value:
a)A quarter of an hour is 15 minutesb)There is caffeine in coffee.c)The ocean has salt water.