Final answer:
To determine whether a function is onto, check if every element in the co-domain has a corresponding element in the domain. If yes, the function is onto. If a function is both injective and surjective, it is bijective mapping. A constant mapping has the same output regardless of the input.
Step-by-step explanation:
To determine whether a function is onto, we need to check if every element in the co-domain has a corresponding element in the domain. If every element in the co-domain has a pre-image in the domain, then the function is onto, also known as surjective.
A surjective mapping is a function that has a one-to-one correspondence between the domain and the co-domain. In simpler terms, it means that every element in the co-domain is mapped to by at least one element in the domain.
If a function is both injective (one-to-one) and surjective (onto), then it is called bijective mapping.
A constant mapping, on the other hand, is a function where the output is constant regardless of the input. In a constant mapping, every element in the co-domain is mapped to the same element in the domain.