Image And The Preimage. Now let me ask you an interesting question and this is kind of for bonus points. Preimage we go from a subset of our codomain and we say what subset of our domain maps into that subset of our codomain.
In words the image f x of x is the set of all things in b that f sends elements of x to. 1 27 image of the empty set 2 15 parabola function g x x 2 3 14 example left as an exercise 3 49 the definition of the preimage of a set 5 11 disclaimer. Roughly speaking you might think of f x as a kind of distorted copy or image of x in b the preimage f 1 y of y is the set of all things in a that f sends into y.
The image of an ordered pair is the average of the two coordinates of the ordered pair.
To tell them apart they will usually be defined separately. Now let me ask you an interesting question and this is kind of for bonus points. Roughly speaking you might think of f x as a kind of distorted copy or image of x in b the preimage f 1 y of y is the set of all things in a that f sends into y. Preimage of a set has nothing to do.