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Subsection 1.1 Families of Functions Exercises

  1. For each function given in ItemΒ 1.e.i to ItemΒ 1.e.x:
    1. Determine to which function family you think the function belongs.
    2. Use Desmos to graph the function, and describe in words how it compares to the basic version of the function.
    3. Describe the domain of the given function.
    4. Describe the range of the given function.
    5. State whether the function is even, odd, or neither even nor odd.
      1. \(\displaystyle f(x)=x^2+4\)
      2. \(\displaystyle g(x)=x^3-6x\)
      3. \(\displaystyle h(x)=\sqrt{x-2}\)
      4. \(\displaystyle k(x)=|x^2-4|\)
      5. \(\displaystyle m(x)=\ln(x+1)+3\)
      6. \(\displaystyle n(x)=\sqrt[3]{x^3-2x}\)
      7. \(\displaystyle p(x)=x^2+\sqrt{x}\)
      8. \(\displaystyle q(x)=x^3+x^{\frac{1}{3}}\)
      9. \(\displaystyle r(x)=3^{2x}\)
      10. \(\displaystyle s(x)=\frac{1}{x+7}\)
  2. Refer to the function \(g(x)=\frac{1}{2}e^{.05x}\text{.}\)
    1. Find a function equation for the inverse function, \(g^{-1}\text{.}\)
    2. What are the domain and range of \(g^{-1}\text{?}\)
    3. Graph \(g(x)\) and \(g^{-1}(x)\) on the same set of axes.
    4. Solve \(g(x) \leq 2\text{.}\)
  3. Refer to the population of Egypt, for given years as shown in TableΒ 1.1.15.(Source: https://www.worldometers.info/world-population/egypt-population/)
    Table 1.1.15. Population, \(P(t)\) (in millions of people), of Egypt \(t\) years after 1985
    \(t\) 0 5 10 15 20 25 30
    \(P(t)\) 50.2 57.4 63.7 69.9 76.8 84.1 93.8
    1. Using the population of Egypt in 1985 and 2015, build an exponential model for the population, \(P(t)\text{,}\) \(t\) years after 1985.
    2. Using the population of Egypt in 1985 and 2015, build a linear model for the population, \(P(t)\text{,}\) \(t\) years after 1985.
    3. Use your exponential model to predict the population of Egypt in 2010. How does your prediction compare with the actual population at that time?
    4. Use your linear model to predict the population of Egypt in 2010. How does your prediction compare with the actual population at that time?
    5. Explain whether the linear or the exponential model is a better fit to the population data.
    6. Use your exponential model to predict in what year the population of Egypt will reach 150 million. First give your answer in exact form using a logarithm, and then give the decimal approximation.
    7. Use the exponential model \(P(t)\) to predict the population of Egypt in 2019. Compare your answer to the actual population of 101.2 million.
  4. Solve the following equations.
    1. \(\displaystyle 5\cdot 2^{3x}= 20480\)
    2. \(\displaystyle 243^{6x}-151=578\)
    3. \(\displaystyle 9^{2x}-23\cdot9^x - 108 = 0\)
    4. \(\displaystyle \ln(x-1) + \ln(x-4) = \ln 70\)
    5. \(\displaystyle 3^{3x}\cdot6^x=\frac{1}{2916}\)
  5. Let \(f(x)=3^x\text{,}\) \(g(x)=15e^{3x}\text{,}\) and \(h(x)=\sqrt{x}\text{.}\)
    1. Write an expression for \(f(x)g(x)\text{.}\)
    2. Let \(k(x)=h(g(x))\text{.}\) Write an expression for \(k(x)\text{.}\)
    3. Write an expression for \(g^{-1}(x)\text{,}\) the inverse of \(g(x)\text{.}\)
    4. Find the exact solution to \(f(x)\geq g(x)\text{,}\) and express the solution using interval notation.