Answer:
A function f is onto if and only if, each element in the codomain of f is the image of at least one element in the domain of f.
Step-by-step explanation:
A function f is onto if and only if, each element in the codomain of f is the image of at least one element in the domain of f.
Let us consider a function f which maps the elements of X to each element in the domain of f, such that
f(1) = D
f(2) = B
f(3) = C
f(4) = C
From here, we can determine the domain and range, so
Domain X of f = {1, 2, 3, 4}
Domain Y of f = {D, B, C}
Therefore, it is clear that every element in the codomain of f is the image of at least one element in the domain of f.
