Listed below are some functions we’ll encounter frequently. Note carefully their domains and ranges and how they have been plotted.
1. Constant function \(f\,(x) = k\)
Domain = \(\mathbb{R}\)
Range = \(\{ k\} \)

2. Identity function \(f\,(x) = x\)
Domain = \(\mathbb{R}\)
Range = \(\mathbb{R}\)

3. Linear function \(f\,(x) = mx + c\)
Domain = \(\mathbb{R}\)
Range = \(\mathbb{R}\)

4. Square function \(f\,(x) = {x^2}\)
Domain = \(\mathbb{R}\)
Range = [0, \(\infty\))

5. Cube function \(f\,(x) = {x^3}\)
Domain = \(\mathbb{R}\)
Range = \(\mathbb{R}\)
