Problem
Complete the sentence below. Given two functions $f$ and $g$, the , denoted $f \circ g$, is defined by $f \circ g(x)=$ Given two functions $\mathrm{f}$ and $\mathrm{g}$, the denoted $f \circ g$, is defined by $f \circ g(x)=$
Solution
Step 1 ：Given two functions $f$ and $g$, the composition of functions, denoted $f \circ g$, is defined by $f \circ g(x) = f(g(x))$. This means that we first apply the function $g$ to $x$, and then apply the function $f$ to the result.
Step 2 ：Final Answer: $f \circ g(x) = \boxed{f(g(x))}$
