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Beginning Activity Beginning Activity 1: Constructing a New Function

Let \(A = \left\{ {a, b, c, d} \right\}\text{,}\) \(B = \left\{ {p, q, r} \right\}\text{,}\) and \(C = \left\{ {s, t, u, v} \right\}\text{.}\) The arrow diagram in FigureĀ 6.23 shows two functions: \(f\x A \to B\) and \(g\x B \to C\text{.}\)

Notice that if \(x \in A\text{,}\) then \(f(x) \in B\text{.}\) Since \(f(x) \in B\text{,}\) we can apply the function \(g\) to \(f(x)\text{,}\) and we obtain \(g(f(x))\text{,}\) which is an element of \(C\text{.}\)

Using this process, determine \(g(f(a))\text{,}\) \(g ( f(b) )\text{,}\) \(g ( f(c) )\text{,}\) and \(g ( f(d) )\text{.}\) Then explain how we can use this information to define a function from \(A\) to \(C\text{.}\)

Figure 6.23. Arrow Diagram Showing Two Functions