2.
3 Exponential Functions
AP Precalculus Name: _____________________________ CA #1
Identify if the function is exponential growth or decay and justify your response.
1. 𝑓 𝑥 2.5 2. 𝑓 𝑥 3. 𝑓 𝑥 5.7 0.2 4. 𝑓 𝑥 8 2.1
Exponential Exponential
Exponential Exponential Growth or Decay Growth or Decay
Growth or Decay Growth or Decay
The following values are output values of an exponential function of the form 𝒇 𝒙 𝒂 ∙ 𝒃𝒙 ,
where 𝒂 and 𝒃 are constants. Write the function along with the input value that represents the
output value.
5. 7 ⋅ 7 ⋅ 7 ⋅ 3.4 6. 0.8 ⋅ 0.8 ⋅ 5.2 7. 6 ⋅ 1.3 ⋅ 1.3 ⋅ 1.3 ⋅ 1.3 8. 9 ⋅ 9 ⋅ 9
𝑓 𝑥 𝑓 𝑥 𝑓 𝑥 𝑓 𝑥
where 𝑥 where 𝑥 where 𝑥 where 𝑥
Answer the questions for each exponential function.
9. 𝑓 𝑥 10. 𝑓 𝑥 3 4.5
a. Is the function increasing or decreasing?
a. Is the function increasing or decreasing?
b. Is the function concave up or concave down?
b. Is the function concave up or concave down?
c. Find lim 𝑓 𝑥
c. Find lim 𝑓 𝑥 →
→
d. Find lim 𝑓 𝑥
d. Find lim 𝑓 𝑥 →
→
11. 𝑓 𝑥 5 0.8 12. 𝑓 𝑥 2 6
a. Is the function increasing or decreasing? a. Is the function increasing or decreasing?
b. Is the function concave up or concave down? b. Is the function concave up or concave down?
c. Find lim 𝑓 𝑥 c. Find lim 𝑓 𝑥
→ →
d. Find lim 𝑓 𝑥 d. Find lim 𝑓 𝑥
→ →
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Answers to 2.3 CA #1
1. Decay because 𝑎 0 and 2. Decay because 𝑎 0 and 3. Decay because 𝑎 0 and 4. Growth because 𝑎 0
0 𝑏 1 0 𝑏 1 0 𝑏 1 and 𝑏 1
5. 𝑓 𝑥 3.4 7 where 𝑥 3 6. 𝑓 𝑥 5.2 0.8 where 𝑥 2 7. 𝑓 𝑥 6 1.3 where 𝑥 4
9. 10. 11. 12.
a. Decreasing a. Increasing a. Increasing a. Decreasing
b. Concave up b. Concave up b. Concave down b. Concave down
8. 𝑓 𝑥 9 where 𝑥 3 c. lim 𝑓 𝑥 ∞ c. lim 𝑓 𝑥 0 c. lim 𝑓 𝑥 ∞ c. lim 𝑓 𝑥 0
→ → → →
d. lim 𝑓 𝑥 0 d. lim 𝑓 𝑥 ∞ d. lim 𝑓 𝑥 0 d. lim 𝑓 𝑥 ∞
→ → → →
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