The composition of the functions is is applying one function to the results of another. Then [tex] (g\circ f)(x)=g(f(x)) [/tex].
If [tex] f(x)=\dfrac{1}{x} [/tex], then
[tex] g(f(x))=g\left(\dfrac{1}{x}\right) [/tex].
If [tex] g(x)=\dfrac{1}{x} [/tex], then
[tex] g(f(x))=g\left(\dfrac{1}{x}\right)=\dfrac{1}{\frac{1}{x}}=x [/tex].
Answer: [tex] (g\circ f)(x)=x [/tex].
