1. 5.3 Conjunctions & Disjunctions
Objective:

• To determine whether a conjunction or disjunction is true or false

Frameworks: 10.P.1, 10.P.7

2. Examples
To go on coop, a junior must maintain a minimum grade of 75 in both shop and related,
and maintain an overall academic average of 75, with no failures.
and not have been suspended from school during the previous 6 weeks.

3. Examples
To graduate from Monty Tech, a student must take Gym or JROTC every year.

4. Conjunction
A conjunction is composed of 2 sentences connected by the word and.
Whether a conjunction is true or false depends on the 2 sentences:
5 < 8 and 2 + 9 = 11
true trueTRUE
6 4 = 2 and -3 > 1
true false FALSE
2 < 0 and 8 = 5 + 4
false falseFALSE

5. True or False?
5 2 = 7 and 6 4 = -1
-7 + 3 < -2 and 6 3 > 1
6 + 5 < 2 and 2 3 > 1
5 8 < 0 and 8 5 > 0

6. Disjunction
A disjunction is composed of 2 sentences connected by the word or.
Whether a disjunction is true or false depends on the 2 sentences:
5 > -2 or 8 + 2 = 10
true trueTRUE
5 * 8 = 40 or 9 10 = 1
true false TRUE
6 < -4 and 3 * 5 = 10
false falseFALSE

7. A disjunction is false . . .
only if both sentences are false.

8. True or False?
5 2 = 7 or 6 4 = -1
-7 + 3 < -2 or 6 3 > 1
53 < 100 or 6 * 8 = 50
5 8 < 0 or 8 5 > 0

9. Truth tables
http://en.wikipedia.org/wiki/Truth_table

10. Example
In a laboratory stress test, a tube of material is found to fail if it is stretched to a length of more than 21.3 cm or compressed to a length of less than 19.7 cm. Use a conjunction or disjunction to describe the complete failure zone for the material.
x < 19.7 or x > 21.3

11. Turn to p. 177
Do 1 -8, 1-14