A Function
It is a functional relationship which has an input and an output. Addition, subtraction, multiplication, division, reciprocals, exponentials, logarithms are all examples.
It is a injective relationship. However, it need not be surjective and so will not be bijective. It will, therefore, not define an invertible function.
There need not be any relationship.
A function.
Relation
function
A one-to-one or injective function.
The relationship is called a surjection or a surjective function.
It is a functional relationship which has an input and an output. Addition, subtraction, multiplication, division, reciprocals, exponentials, logarithms are all examples.
A calculator
cost output relationship
Output from what? Of a mathematical function? Of a computer procedure? Of a machine? Of a river? And what type of output? Please clarify your question.
It is a injective relationship. However, it need not be surjective and so will not be bijective. It will, therefore, not define an invertible function.
A function is any relationship between inputs and outputs in which each input leads to exactly one output. It is possible for a function to have more than one input that yields the same output.
There need not be any relationship.
The relationship between two variables is called a relation. A relation in which a set of input values maps onto a set of output values such that each input corresponds to at most one output is called a "function." Functions do not necessarily have to be lines; they do not even have to be exponential, or parabolic, or continuous. A bunch of scattered points or lines that meets the requirements can still be considered a function involving two variables.
A monitor is the "gateway" to your computer. It is the output of your computer. E.g. a mathematical formula has an input, an output and an algorithm. The keyboard & mouse is the input, the computer is the algorithm, and the monitor is the output.