1. Two marks example problems I

Let \(X = \{1\), \(2\), \(3\), \(4\}\) and \(Y = \{2\), \(4\), \(6\), \(8\), \(10\}\) and \(\mathbb{R} = \{(1, 2)\), \((2, 4)\), \((3, 6)\), \((4, 8)\}\). Show that \(\mathbb{R}\) is a function and find its domain, co-domain, and range?

 

\(\mathbb{R}\) is a functionnot a function.

 

Domain \(=\) $\left\{i,i,i,i\right\}$

 

Co-domain \(=\) $\left\{i,i,i,i,i\right\}$

 

Range \(=\) $\left\{i,i,i,i\right\}$