Week 1. Flashcards
(28 cards)
Set
Group of Elements notated {element 1, …}
∈
Element Belongs to a Set
∉
Element doesn’t belong to a set
⊆
Subset relationship
or :
Such that
Special-Sets
Sets of numbers that have their own special symbols
N
Set of Natural numbers {1,2,3, …}
Z
Set of Integer Numbers (whole number)
Q
Set of ratio numbers p/q where p,q ∈ Z
R
Most important. The set of all real numbers
0
Empty set {}
Union U
The set that contains all elements of 2 sets
Intersection n
The set that contains all elements which are in both sets
Exclusion
The set that contains all elements in one set that aren’t in the other A/B
Interval
The set containing all real numbers between two bounds a,b where a,b ∈ R. Can be closed or open
Closed Interval
Set contains the bounds of the interval [a,b]
Open Interval
Set excludes the bounds of the interval (a,b)
Infinity & Intervals
Infinity and -Infinity are concepts not real numbers, so shouldn’t be included in an interval set. Therefore, any interval containing -infinity, infinity will be open on the infinity side.
Function
Consists of a domain (set A), a co-domain (Set B), and a rule that sends and element x in the domain to exactly one element in the co-domain f(x). There maybe cases where the rule doesn’t map to any elements in the co-domain
Vertical Line test
Test if a rule is a function by graphing it, if a vertical line put through it intersects it at 2 or more times at any point it isn’t a function.
Range
Set of all elements that a fucntion will actually output (lowest output, highest output)
Combining functions
Functions can be added, subtracted, multiplied, or divided
Composition function
X’s or variables in function f(x) replaced with another function g(x). Notated f(g(x)).
Piecewise functions
different rules applied to different areas of the domain of the function