Section 4.1
Moving from Sets to Functions
Activity 1
• Let:
– M = {Ham, Turkey, Roast Beef, Pastrami}
– C = {American, Cheddar, Swiss}
• What is MxC?
Activity 1
• Let:
– M = {Ham, Turkey, Roast Beef, Pastrami}
– C = {American, Cheddar, Swiss}
• What is MxM?
Activity 1
• Let:
– M = {Ham, Turkey, Roast Beef, Pastrami}
– C = {American, Cheddar, Swiss}
• Describe how CxM compares to MxC?
Activity #2
•
•
•
•
Function
Domain
Target
Range
Definition of a function
• A function f from a set X to a set Y, denote
f: X → Y, is a relation from X, the domain
to Y, the target (or co-domain) that satisfies
two properties:
1. Every element in X is related to some element
in Y
2. No element in X is related to more than one
element in Y
Activity 3
Activity 4
• f(x) = the town person x was born in
• f(x) = the schools person x went to
• f(x) = the college that person x graduated
from
• f(x) = x + 5
• f(x) = 3 if x>2 otherwise f(x) = -2
• f(x) = 7 if x>0 or f(x) = -7 if x<0 or f(x) = 7
or -7 if x = 0