Inverse Functions Practice

Visit this page directly at hunkim.com/inverse

  1. f(x)=3x-2. Find f^{-1}(x)
    Solution
    \frac{x+2}{3}

  2. f(x)=(x-2)^2, x\geq 2
    1. Find f^{-1}(x)
      Solution
      \sqrt{2}+2

    2. Domain and range of f(x)
      Solution
      x\geq2 and y\geq0

    3. Domain and range of f^{-1}(x)
      Solution
      x\geq0 and y\geq2

  3. The point (2,3) is on f(x)
    1. What point must be on f^{-1}(x)?
      Solution
      (3,2)

    2. What point must be on y=2f\left(\frac{x}{2}-1\right)?
      Solution
      (6,6)

    3. What point must be on 3-3f^{-1}(2x)?
      Solution
      \left(\frac{3}{2},-3\right)

  4. See f(x) below:

    Sketch f^{-1}(x) on top of the graph above
    Solution


  5. In general, f(x) reflects f^{-1}(x) along which line?
    Solution
    y=x

  6. Simplify y=f\left(f^{-1}(x)\right)
    Solution
    5

  7. g(x)=x^2 and f(x)=x^{1/2}
    h(x)=g\left(f(x)\right). True or False: Since g(x) and f(x) “undo” each other, h(-4)=-4
    Solution
    False, g has an undefined input
  8. f(x)=3e^{x-2}. Find f^{-1}(x)
    Solution
    \ln x-\ln3+2

  9. Challenge: f(x)=x^2+6x+2. Find f^{-1}(x)
    Solution
    Completing the square on y we get the relation:
    f^{-1}(x)=\pm\sqrt{x+7}-3