Concepts and Vocabulary
True or False If every vertical line intersects the graph of a function \(f\) at no more than one point, \(f\) is a one-to-one function.
If the domain of a one-to-one function \(f\) is \([4,\infty)\), the range of its inverse function \(f^{-1}\) is _____.
True or False If \(f\) and \(g\) are inverse functions, the domain of \(f\) is the same as the domain of \(g\).
True or False If \(f\) and \(g\) are inverse functions, their graphs are symmetric with respect to the line \(y = x\).
True or False If \(f\) and \(g\) are inverse functions, then \((f \circ g) (x) = f(x) \,\cdot\, g(x)\).
True or False If a function \(f\) is one-to-one, then \(f (f^{-1}( x)) = x\), where \(x\) is in the domain of \(f\).
Given a collection of points \((x,y)\), explain how you would determine if it represents a one-to-one function \(y = f(x)\).
Given the graph of a one-to-one function \(y = f(x)\), explain how you would graph the inverse function \(f^{-1}\).
Practice Problems
In Problems 9–14, the graph of a function f is given. Use the Horizontal-line Test to determine whether f is one-to one.
In Problems 15–18, verify that the functions f and g are inverses of each other by showing that \((f\circ g)(x) = x\) and \((g\circ f)(x) = x\).
\(f( x) =3x+4\); \(g( x) = \dfrac{1}{3}( x-4)\)
\(f( x) = x^{3}-8\); \(g(x) = \sqrt[3]{x+8}\)
\(f(x) = \dfrac{1}{x}\); \(g(x) = \dfrac{1}{x}\)
\(f(x) = \dfrac{2x+3}{x+4}\); \(g(x) = \dfrac{4x-3}{2-x}\)
In Problems 19–22, (a) determine whether the function is one-to-one. If it is one-to-one, (b) find the inverse of each one-to-one function. (c) State the domain and the range of the function and its inverse.
\(\{(-3,5), (-2,9), (-1,2), (0,11), ( 1,-5)\}\)
\(\{(-2,2), (-1,6), ( 0,8), ( 1,-3), ( 2,8)\}\)
\(\{(-2,1), (-3,2), (-10,0), (1,9), ( 2,1)\}\)
\(\{(-2,-8), (-1,-1), (0,0), (1,1), (2,8)\}\)
In Problems 23–28, the graph of a one-to-one function f is given. Draw the graph of the inverse function. For convenience, the graph of \(y=x\) is also given.
In Problems 29–38, the function f is one-to-one.
\(f(x) = 4x + 2\)
\(f(x) = 1-3x\)
\(f(x) = \sqrt[3]{x+10}\)
\(f(x) = 2x^{3}+4\)
\(f(x) = \dfrac{1}{x-2}\)
\(f(x) = \dfrac{2x}{3x-1}\)
\(f(x) = \dfrac{2x+3}{x+2}\)
\(f(x) = \dfrac{-3x-4}{x-2}\)
\(f(x) = x^{2}+4\), \(x\geq 0\)
\(f(x) = (x-2)^{2}+4\), \(x\leq 2\)