Sets

Question 1

What is a set?

Answer 1

A collection of unordered, distinct objects called elements represented by {curly brackets}

Question 2

What does unordered and distinct mean?

Answer 2

The order doesn’t matter - 0,1,5 is same as 1,5,0

Distinct means each element is unique; repeated elements are listed once in a set

Question 3

What are three important sets in math?

Answer 3

Set N = natural numbers = counting, 1, 2, 3,…
Set Z = integers (whole numbers) = …,-2,-1,0,1,2,…
Set Q = rational numbers = any number that can be represented by a simple fraction

Question 4

What an irrational number? What’s an example?

Answer 4

A number that can’t be written as a simple fraction

Pi, e, golden ration, square root of 2

Question 5

What is the symbol for inclusion? Exclusion? Write out square is included in set B

Answer 5

Inclusion = Epsilon, ε
Exclusion = Epsilon crossed out
Square ε B

Question 6

What is cardinality? How is it represented?

Answer 6

The size of the set, number of elements in a set

Two straight lines on both sides (looks like abs. value)

Question 7

What are real numbers? What are imaginary numbers? What is i?

Answer 7

Real numbers are all rational + irrational numbers (all numbers on a number line)
Imaginary numbers are even roots of a negative number, the imaginary number i = sq rt of -1

Question 8

What are complex numbers?

Answer 8

Complex numbers are combinations of real and imaginary numbers (a+bi)