Define three different functions $f_{i}: mathbb{R} ightarrow mathbb{R}, i in{1,2,3}$ in such a way that - $f_{1}$ is an injection but not a surjection,

Define three different functions $f_{i}: \mathbb{R} \rightarrow \mathbb{R}, i \in\{1,2,3\}$ in such a way that

- $f_{1}$ is an injection but not a surjection,

- $f_{2}$ is a surjection but not an injection,

- $f_{3}$ is a bijection.