Graph (mapping)/R and R^2/Imagination/Exercise

How can we visualize the graph of a mapping

$\varphi \colon \mathbb {R} ^{2}\longrightarrow \mathbb {R} ,$

and the graph of a mapping

$\varphi \colon \mathbb {R} \longrightarrow \mathbb {R} ^{2}?$

Create a solution