Question

Which condition represents an onto (surjective) function?

Options

• \(x_1\ne x_2\text{ but }f(x_1)=f(x_2)\)

• \(f(x_1)=f(x_2)\Rightarrow x_1=x_2\)

• \(\text{Range}=\text{Codomain}\)

• \(\text{Range}\subset\text{Codomain}\)

Answer 1

An onto function reaches every element of its codomain. Therefore, its range and codomain are equal, written as \[\text{Range}=\text{Codomain}\].