Let
$$f : \mathbb{R} → \mathbb{R}, f(x) = 3^3 + 2$$
I know it's not onto actually, because it doesn't give all the real numbers. But is it one-to-one, even though we're not actually using the x variable for anything?
Thanks!
[Math] Is this function one-to-one and onto
discrete mathematicsfunctions
Best Answer
It is a constant function and constant function is neither one one nor onto if domain and codomain has cardinality bigger than $1$. As all elements are going to same value, so if domain has cardinality greater than $1$ (in your case domain is $\mathbb{R}$, so cardinality is much bigger than $1$ ), it is many one, not one-one