Image

Assume a function that maps from a set X to a set Y.

We write this as follows:

f : x –> y

Image of an Element

Let x be an element of X, then f(x), which is an element of Y, is the image of x.

Image of a Subset

Let A be a subset of X. For every x in A, f(x) is in the Image of A.

An example: if f(x)=2x then the image of {1,2,3} is {2,4,6}.

Image of a Function

The image of a function of the image of its entire domain (here we are using the definition for the image of an element and applying it to all the elements of X.)

If our function is f(x)=2x and the domain is [2,6] then the image is [4,12].