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Functions & relations

Injective and surjective maps

1 / 5Standard

Which describes the map f: injective, surjective, both or neither?

f:{1,2,3,4}→{1,2,3,4,5}x1234f(x)2415\begin{array}{l} f: \left\{1, 2, 3, 4\right\} \to \left\{1, 2, 3, 4, 5\right\} \\ \begin{array}{c|cccc} x & 1 & 2 & 3 & 4 \\ \hline f(x) & 2 & 4 & 1 & 5 \end{array} \end{array}