Comparing functions

Practice sheet

Fresh questions from the whole chapter, to do on paper.

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  1. What is the domain of f(x)=x−9f(x) = \sqrt{x - 9}? Give it as an interval.
  2. What is the domain of f(x)=9x−6f(x) = \dfrac{ 9 }{x - 6}? Give it as an interval or a union of intervals.
  3. What is the range of f(x)=(x−5)2+9f(x) = (x - 5)^2 + 9? Give it as an interval.
  4. Find the average rate of change of f(x)=3x2f(x) = 3x^2 from x=0x = 0 to x=6x = 6.
  5. f(x)=−(x−5)2+8f(x) = -(x - 5)^2 + 8. On which interval is ff increasing?
    1. (−∞,5)(-\infty, 5)
    2. (5,∞)(5, \infty)
    3. (−∞,8)(-\infty, 8)
  6. A tank holds 16 liters at time 0 and 6161 liters after 5 minutes. What is the average rate of change of the volume, in liters per minute?
  7. A table gives x=0,1,2,3x = 0, 1, 2, 3 and y=4,12,36,108y = 4, 12, 36, 108. What kind of relationship is it?
    1. Exponential: yy is multiplied by 3 at each step
    2. Linear: yy goes up by 8 at each step
    3. Neither
  8. An exponential function has g(0)=9g(0) = 9 and g(1)=18g(1) = 18. Find g(3)g(3).
  9. f(x)=57x+380f(x) = 57x + 380 and g(x)=1.04xg(x) = 1.04^x. For very large xx, which is greater?
    1. gg: exponential growth eventually overtakes linear growth
    2. ff: it is greater now and grows faster
    3. They stay about equal
  10. An exponential function ff has f(0)=9f(0) = 9, and each time xx increases by 1, the value of ff is multiplied by 5. Write f(x)f(x).
  11. A population is 7 thousand at t=0t = 0 and is multiplied by 3 every 4 years. Write the population P(t)P(t), in thousands, after tt years.
  12. Plot the points of the graph of f(x)=4⋅2xf(x) = 4 \cdot 2^x at x=0x = 0 and x=1x = 1.