加载中...
加载中...
Assessment for Unit 2: Exponential and Logarithmic Functions
Select the one best answer for each question.
1. A landscaping company plants a tree that is currently 150 cm tall. The tree is expected to grow by 12 cm each year. If $h_n$ represents the height of the tree in centimeters after $n$ years, which of the following equations best models the height of the tree?
2. A new car is purchased for 30,000 dollars. The value of the car is expected to depreciate by 15% each year. If $v_n$ represents the value of the car, in dollars, after $n$ years, which of the following equations best models the value of the car?
3. The graph of the sequence $a_n$ consists of the discrete points $(0, 3)$, $(1, 6)$, $(2, 12)$, and $(3, 24)$. Which of the following defines the general term $a_n$ for $n \ge 0$?
4. Consider a sequence where the initial term is $a_0 = 8$ and the first term is $a_1 = 12$. Let $A$ be the value of the term $a_2$ if the sequence is arithmetic, and let $G$ be the value of the term $a_2$ if the sequence is geometric. What is the value of $G - A$?
5. The function $g$ is defined by $g(x) = 5^x$. The function $f$ is the inverse of $g$. Which of the following tables best represents selected values for the function $f$?
6. The graph of the function $h$ is given by $h(x) = 3^x$. The function $k$ is the inverse of $h$. Which of the following statements is true regarding the graph of $k$?
7. Values of a function $f$ are given in the table below.$\n\n$| x | 2 | 4 | 8 | 16 |$\n$|---|---|---|---|----|$\n$| f(x) | 1 | 2 | 3 | 4 |$\n\nWhich $of the following statements best describes the relationship between the inputs and outputs of $f$, confirming that $f$ models logarithmic growth?
8. The function $f$ is given by $f(x) = e^x$. If the function $g$ is the inverse of $f$, what is the value of $g(e^{-3})$?
9. The function $f$ is defined by $f(x) = \log_b x$, where $b$ is a constant such that $0 < b < 1$. Which of the following statements is true about the graph of $f$?
10. The table below gives values for a function $g$ for selected values of $x$. | $x$ | 2 | 6 | 18 | 54 | | :--- | :---: | :---: | :---: | :---: | | $g(x)$ | 3 | 5 | 7 | 9 | Which of the following statements best explains why $g$ could be a logarithmic function?
11. Let $f$ be the function given by $f(x) = \ln x$. Let $R_A$ be the average rate of change of $f$ over the interval $[2, 4]$, and let $R_B$ be the average rate of change of $f$ over the interval $[10, 12]$. Which of the following correctly compares $R_A$ and $R_B$ and provides a valid justification?
12. Consider the function $h(x) = \log_{10}(x)$. Which of the following describes the end behavior and asymptotic behavior of the graph of $h$?
13. [Skill: 1.B | Topic: 2.12] A student is using a calculator that has only the natural logarithm function, $\ln$. To evaluate the expression $\log_{5}(x^3)$ for positive values of $x$, the student rewrites it using logarithm properties. Which of the following expressions is equivalent to $\log_{5}(x^3)$ for $x>0$?
14. Which of the following functions is equivalent to $g(x) = \log_{16}(x)$ for all $x > 0$?
15. If $u = \ln x$ and $v = \ln y$, which of the following expressions is equivalent to $\ln \left( \frac{e^3 \sqrt{x}}{y^2} \right)$?
16. Solve the equation $\log_{2}(x) + \log_{2}(x-2) = 3$ for $x$.
17. The function $f$ is given by $f(x) = 2\log_{3}(x-1) + 4$. Which of the following defines the inverse function $f^{-1}$?
18. What are all values of $x$ for which $\left(\frac{1}{2}\right)^{x+2} \geq 4^{2x-1}$?
19. The table below shows values for the function $f$ at selected values of $x$. | $x$ | $2$ | $6$ | $18$ | $54$ | | :---: | :---: | :---: | :---: | :---: | | $f(x)$ | $5$ | $8$ | $11$ | $14$ | Which of the following function models is most appropriate for the relationship shown in the table?
20. A researcher is modeling the height of a plant, $h(t)$, in centimeters, as a function of time $t$ in days using the function $h(t) = a + b \ln t$. The researcher collects the following data: at $t=1$ day, the height is $12$ cm, and at $t=e^2$ days, the height is $18$ cm. Based on this model, what is the predicted height of the plant at $t=e^5$ days?
21. Students are analyzing a set of bivariate data $(x, y)$ to determine the best function model. They produce four different scatterplots using transformations of the data. Which of the following scatterplot descriptions indicates that the data should be modeled by a logarithmic function of the form $y = a + b \ln x$?
22. [Skill: 2.B | Topic: 2.15] The relationship between variables $x$ and $y$ is analyzed using a semi-log plot where the vertical axis is logarithmically scaled with base 10. The trend line for the data on this semi-log plot is given by the equation $\log_{10} y = 0.4x + 1.2$. Which of the following exponential functions best models the relationship between $x$ and $y$?
23. [Skill: 3.B | Topic: 2.15] A researcher collects the following data for an independent variable $t$ and a dependent variable $P$: | $t$ | 0 | 2 | 4 | 6 | |---|---|---|---|---| | $P$ | 5.0 | 15.0 | 45.0 | 135.0 | The researcher wishes to determine if an exponential model is appropriate for this data set. Which of the following plots would result in a linear configuration of data points?
24. [Skill: 2.A | Topic: 2.15] A semi-log plot displays the relationship between $x$ and the natural logarithm of $y$, denoted as $\ln y$. The graph shows a straight line passing through the points $(0, 3)$ and $(2, 4)$. Which of the following functions correctly models the relationship between $y$ and $x$?
Refer to the figure below.
25. The table below gives values for a function $g$ at selected values of $x$. Which of the following statements is true regarding the type of function that best models $g$?
26. A quantity is measured at time $t=0$ to be 200. At time $t=3$, the quantity is measured to be 160. Let $L(t)$ be a linear model for the quantity and let $E(t)$ be an exponential model for the quantity. Which of the following compares the predicted values of the quantity at $t=6$ using the two models?
27. The table below shows values for a function f at selected values of x . | x | 2 | 4 | 6 | 8 | |---|---|---|---|---| | f(x) | 12 | 18 | 27 | 40.5 | Which of the following claims about f is true?
28. Let g be the function defined by g(x) = -3(0.4)^x . Which of the following describes the behavior of the graph of g in the xy -plane?
29. A biological culture contains a population of bacteria, P , that changes with time, t , measured in hours. The population triples every 5 hours. If the initial population is P_0 , which of the following functions models the population P(t) ?
30. The exponential function $f$ is defined by $f(x) = 8(2)^{x-3}$. Which of the following is an equivalent form of $f(x)$ that shows the function as a vertical dilation of the parent function $g(x) = 2^x$?
31. The function $g$ is given by $g(x) = 3(16)^{3x/4}$. Which of the following is an equivalent form of $g(x)$?
32. A scientist models the population of a specific bacteria colony with the function $P(t) = 500(1.4)^t$, where $t$ represents the time in days. Which of the following functions $M$ models the population where $m$ represents the time in hours?
33. The table below gives values for a function $f$ at selected values of $x$. Which of the following statements explains why $f$ could be best modeled by an exponential function? | $x$ | 2 | 4 | 6 | 8 | |---|---|---|---|---| | $f(x)$ | 16 | 24 | 36 | 54 |
34. A biologist models the population of a bacterial colony with the function $P(t) = 500(1.08)^{2t}$, where $t$ is measured in hours. Which of the following is the best interpretation of the parameter $1.08$ in the context of this model?
35. The value of a vintage car, $V(t)$, in thousands of dollars, is modeled by an exponential function of time $t$ in years. When $t=0$, the value of the car is 20 thousand dollars. When $t=3$, the value of the car is 25 thousand dollars. Which of the following expressions defines $V(t)$?
36. A researcher collects data on the population of a specific bacteria culture over time. The table below shows the population, $P(t)$, in thousands, at various times $t$ in hours. | $t$ (hours) | $P(t)$ (thousands) | | :---: | :---: | | 0 | 12.00 | | 2 | 18.00 | | 4 | 27.00 | | 6 | 40.50 | Based on the data in the table, which of the following function types best models the relationship between $t$ and $P(t)$, and why?
37. A student uses a regression calculator to fit a linear model, $y = ax + b$, to a set of data points $(x, y)$. To validate whether the linear model is appropriate, the student generates a residual plot. The residual plot shows a distinct U-shaped pattern, with positive residuals for low and high $x$-values and negative residuals for middle $x$-values. Which of the following is the correct conclusion based on this residual plot?
38. The table below gives values for the variables $x$ and $y$. | $x$ | 1 | 2 | 3 | 4 | 5 | |:---:|:---:|:---:|:---:|:---:|:---:| | $y$ | 4.2 | 7.8 | 11.4 | 15.0 | 18.6 | A student is deciding between a linear and an exponential model for the data. Which of the following statements provides the strongest evidence for selecting a linear model?
39. The function $f$ is given by $f(x) = 5 - e^{x+3}$. Which of the following defines the inverse function $f^{-1}$ ?
40. The function $g$ is defined by $g(x) = 2\log_4(x - 3) + 1$. What are the domain and range of the inverse function, $g^{-1}$ ?
41. The population of a colony of bacteria $t$ hours after an experiment begins is modeled by the function $P(t) = 50(2)^{t/4}$. Which of the following is true about the value and interpretation of $P^{-1}(200)$ ?
42. Evaluate the following expression: $$\log_4(32) + \log_9(27)$$
43. Values $A$ and $B$ are plotted on a logarithmic scale with a base of 3. If the position of $B$ is 4 units greater than the position of $A$ on this scale, which of the following statements is true regarding the values of $A$ and $B$?
44. Consider the following logarithmic values: $$x = \log_3(20)$$ $$y = \log_4(20)$$ $$z = \log_5(20)$$ Which of the following correctly orders $x$, $y$, and $z$?
45. [Skill: 2.B | Topic: 2.7] Let $f$ and $g$ be functions defined by $f(x) = e^x$ and $g(x) = \ln(x^4)$ for $x > 0$. Which of the following is an analytic representation of the composite function $h(x) = f(g(x))$?
46. [Skill: 1.C | Topic: 2.7] The functions $f$ and $g$ are defined by $f(x) = 2x - 3$ and $g(x) = \ln(x + 5)$. Which of the following is an analytic representation of $h(x) = f(g(x))$?
47. [Skill: 2.B | Topic: 2.2] The table below shows values for a linear function $f$ and an exponential function $g$ for specific values of $x$. | $x$ | $f(x)$ | $g(x)$ | | :--- | :--- | :--- | | 0 | 4 | 4 | | 2 | 16 | 16 | Which of the following statements is true regarding the values of $f(3)$ and $g(3)$? (A) $f(3) = 22$ and $g(3) = 32$, so $g(3) > f(3)$. (B) $f(3) = 22$ and $g(3) = 22$, so $f(3) = g(3)$. (C) $f(3) = 28$ and $g(3) = 32$, so $g(3) > f(3)$. (D) $f(3) = 22$ and $g(3) = 64$, so $g(3) > f(3)$.
48. Let $f$ and $g$ be functions defined by $f(x) = \frac{1}{x}$ and $g(x) = \ln(x - 3)$. Which of the following defines the domain of the composite function $h$ defined by $h(x) = f(g(x))$?
49. Let $f$ be the function defined by $f(x) = \log_2(x)$. The values of the function $g$ are given in the table below. | $x$ | $2$ | $4$ | $8$ | $16$ | | :---: | :---: | :---: | :---: | :---: | | $g(x)$ | $8$ | $32$ | $4$ | $2$ | What is the value of $(f \circ g)(4)$?
Refer to the figure below.
50. Selected values of the function f are given in the table below. The graph of the function g consists of a line segment connecting the points (0, 4) and (4, 0) . **Table for f(x) :** | x | f(x) | |---|---| | 2 | 4 | | 4 | 16 | | 8 | 64 | What is the value of (g $\circ $f)(2) ?
51. [Skill: 1.B | Topic: 2.7] Let $f(x) = \log_2(x)$ and let $g(x) = 8 - 2^x$. Which of the following defines the domain of the composite function $h(x) = f(g(x))$ ?
52. Let $f(x) = e^{2x}$ and $g(x) = \ln(x)$. Which of the following defines the composite function $h(x) = f(g(x))$ ?
53. [Skill: 1.B | Topic: 2.7] Let $f$ and $g$ be functions defined by $f(x) = \sqrt{x}$ and $g(x) = 2 - \log_3(x)$. What is the domain of the composite function $h$ defined by $h(x) = f(g(x))$?
54. Let $f$ and $g$ be functions defined by $f(x) = e^x$ and $g(x) = \ln(2x - 6)$. Which of the following defines the function $h$ given by $h(x) = (f \circ g)(x)$ ?
55. [Skill: 1.B | Topic: 2.7] Let $f(x) = \ln(x)$ and $g(x) = x^2 - 4x - 5$. Which of the following describes the domain of the composite function $h(x) = f(g(x))$?
56. Let $f$ and $g$ be functions defined by $f(x) = \log_2(x)$ and $g(x) = x^2 - 4x - 12$. Which of the following describes the domain of the composite function $h$ defined by $h(x) = f(g(x))$?
57. Let $f$ and $g$ be functions defined by $f(x) = 2 \cdot 3^{x+1}$ and $g(x) = \log_3(x-1)$. What is the value of $f(g(10))$?
58. The function $f$ is given by the graph below, and the function $g$ is defined by the table of values. [Image Cue]: A graph of a logarithmic function $f(x)$ plotted on the xy-plane. The graph passes through the points $(1, 0)$, $(2, 1)$, $(4, 2)$, and $(8, 3)$. **Table for $g(x)$** | $x$ | $g(x)$ | |---|---| | 1 | 8 | | 2 | 4 | | 3 | 2 | | 4 | 1 | What is the value of $g(f(4))$?
59. [Skill: 2A | Topic: 2.7] A sound engineer uses two functions to model a signal-processing step. The functions are defined by - $f(x)=\ln(x)$ - $g(x)=3^x$ Which of the following correctly states the value of $(f\circ g)(-2)$ and whether $(g\circ f)(-2)$ is defined for real numbers?
Answer all parts of each question. Answers must be in essay form. Outlines or lists alone are not acceptable.
Question 60:
Question 61:
Question 62:
Question 63: