Linear and exponential functions

Practice sheet

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

To save a PDF, choose “Save as PDF” in the print dialog.

  1. 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
  2. An exponential function has g(0)=9g(0) = 9 and g(1)=18g(1) = 18. Find g(3)g(3).
  3. 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
  4. A culture starts with 7 grams of algae. Each week, the amount is multiplied by 3. How many grams are there after 3 weeks?
  5. A photo is 8000 pixels wide. Each time it is resized, its width loses 40%. Write the width W(t)W(t) after tt resizes.
  6. The amount of algae starts at 5 m² and is multiplied by 4 each week. Complete the table.
  7. f(x)=24⋅4xf(x) = 24 \cdot 4^x. Find f(−1)f(-1).
  8. Is f(x)=4⋅(14)xf(x) = 4 \cdot \left(\tfrac{1}{ 4 }\right)^x exponential growth or decay?
    1. Decay: each step multiplies by 14\tfrac{1}{ 4 }
    2. Growth, because 4 is greater than 1
    3. A linear decrease
  9. The graph of an exponential function passes through (0,8)(0, 8) and (1,16)(1, 16). Write f(x)f(x).
  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.