Functions Flashcards
Define functions
a function from a non-empty set A to a non-empty set B is an assignment of each element of A to exactly one element of B
A function is denoted by A –> B
We write f (a) = b if b is the unique element of B assigned by the function f to the element a of A. A clear defined output of one element.
Define function equality
Two functions are equal they have the same domain, the same codomain and map each element of the domain the same element of the codomain
What is a sequence
a sequence is a function from a subset of the integer
What is a geometric progression
a geometric progression is a sequence of the form: a, ar, ar 2 … where the initial term a and the common ratio r are real numbers
What is an arithmetic progression
an arithmetic progression is a sequence of the form a, a + d, a+ 2d, a+3d where the initial term a and the common difference d are real numbers
Define a recurrence relation
a recurrance relation for the sequence a n is an equation that expresses an in terms of one or more of the previous terms of the sequence
How do you solve a recurrence relation
finding the formula for the nth term of the sequence generated by a recurrence relation is called solving the recurrence relation, such a formula is called a closed formula
What does injective mean
one to one, each value in the range of corresponds to exactly one element in the domain, codomain cant have many domain
What does surjective (onto) mean
every element in the codomain maps to at least one element in the domain
What does bijective mean
only one mapping from each element and no value of the codomain is alone. It is both injective and bijective