- #1

TyroneTheDino

- 46

- 1

## Homework Statement

I am supposed to prove or disporve that ##f:\mathbb{R} \rightarrow \mathbb{R}##

##f(x)=\sqrt{x}## is onto. And prove or disprove that it is one to one

## Homework Equations

## The Attempt at a Solution

I know for certain that this function is not onto given the codomain of real numbers, but I am stuck on the one-to-one definition. I believe that I am supposed to disprove it, but I am not sure.

I say disprove because for a function to be one to one all values in the domain must correspond to a value in the codomain. Since anything less than 0 is undefined, does this make it true that not everything in the domain is defined in the codomain. Or is this reasoning flawed? Do only that value that are defined in the domain matter?