Functions and sequences

Practice sheet

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

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  1. A table pairs inputs xx with outputs yy: (x,y)=(5,1),(5,2),(9,3)(x, y) = (5, 1), (5, 2), (9, 3). Is yy a function of xx?
    1. No: the input 5 has two different outputs
    2. Yes: every input has an output
    3. Yes: the outputs are all different
  2. A table pairs inputs xx with outputs yy: (x,y)=(1,5),(5,5),(9,5)(x, y) = (1, 5), (5, 5), (9, 5). Is yy a function of xx?
    1. Yes: each input has exactly one output
    2. No: the output 5 repeats
    3. No: a function needs a formula
  3. A function's rule: multiply the input by 6, then add 6. Which input gives the output 24?
  4. f(x)=2x2+3f(x) = 2x^2 + 3. Find f(−3)f(-3).
  5. f(x)=x2+3f(x) = x^2 + 3. Find f(2+3)f(2 + 3).
  6. Here is the graph of y=f(x)y = f(x). Tap the point of the graph that shows f(2)f(2).
  7. What is the domain of f(x)=x−9f(x) = \sqrt{x - 9}? Give it as an interval.
  8. What is the domain of f(x)=9x−6f(x) = \dfrac{ 9 }{x - 6}? Give it as an interval or a union of intervals.
  9. What is the range of f(x)=(x−5)2+9f(x) = (x - 5)^2 + 9? Give it as an interval.
  10. Find the average rate of change of f(x)=3x2f(x) = 3x^2 from x=0x = 0 to x=6x = 6.
  11. 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)
  12. 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?