Functions flashcards

46 practice cards drawn from the Functions lessons. Tap a card to turn it over. Every answer is checked against the lesson it came from.

Read the Functions lessons in full →

f(x) = 5x + 1. What is f(8)?

41

from “Function Notation”

f(x) = 5x + 6. What is f(5)?

31

from “Function Notation”

f(x) = 1 / (x − 6). Which input is not allowed?

6

from “Domain and Range”

f(x) = x² + 9. What is the smallest output?

9

from “Domain and Range”

f(x) = 4x + 1 for x < 5, and 14 − x for x ≥ 5. What is f(5)?

9

from “Piecewise Functions”

f(x) = 3x + 1 for x < 2, and 10 − x for x ≥ 2. What is f(4)?

6

from “Piecewise Functions”

f(x) = x + 1 for x < 2, and 7 − x for x ≥ 2. Does the graph break at x = 2?

yes, it jumps

from “Graphing a Piecewise Function”

f(x) = x + 1 for x < 3, and 8 − x for x ≥ 3. What is the filled endpoint?

(3, 5)

from “Graphing a Piecewise Function”

f(x) = 3x for x < 2, and x + k for x ≥ 2. Which k joins the pieces?

4

from “Making a Piecewise Function Continuous”

f(x) = 5x for x < 5, and x + k for x ≥ 5. Which k joins the pieces?

20

from “Making a Piecewise Function Continuous”

f(x) = x + 2, g(x) = 3x. What is gf(4)?

18

from “Composite Functions”

f(x) = x + 6, g(x) = 4x. What is gf(3)?

36

from “Composite Functions”

f(x) = 4x + 7. What is the inverse?

(x − 7) / 4

from “Inverse Functions”

f(x) = 3x + 8. What is the inverse?

(x − 8) / 3

from “Inverse Functions”

y = x² + 5. Which way does the curve move?

5 up

from “Transforming Graphs”

y = (x − 2)². Which way does the curve move?

2 right

from “Transforming Graphs”

y = f(x) has a lowest value of 9. What is the lowest value of y = 2f(x)?

18

from “Stretching a Graph Vertically”

(1, 6) is on y = f(x). Where is it on y = 2f(x)?

(1, 12)

from “Stretching a Graph Vertically”

y = f(x) crosses the x-axis at x = 9. Where does y = f(3x) cross?

x = 3

from “Stretching a Graph Horizontally”

Which one squashes the graph of y = f(x) toward the y-axis?

y = f(5x)

from “Stretching a Graph Horizontally”

What is log base 10 of 10000?

4

from “Exponentials and Logarithms”

What is log base 2 of 16?

4

from “Exponentials and Logarithms”

3 multiplied by 2, 4 times over

48

from “Exponential Growth”

3 multiplied by 2, 3 times over

24

from “Exponential Growth”

64 halved 3 times

8

from “Exponential Decay”

48 halved 2 times

12

from “Exponential Decay”

After n half-lives, what fraction of a sample remains?

1/2ⁿ

from “Growth and Decay Problems”

A colony of 100 bacteria doubles every hour. How many after 3 hours?

800

from “Growth and Decay Problems”

Which model stops growing at a ceiling?

P = 200/(1 + 4e⁻ᵗ)

from “Logistic Growth and Carrying Capacity”

P = 125/(1 + 4e⁻ᵗ). What is the carrying capacity?

125

from “Logistic Growth and Carrying Capacity”

log 20 − log 4 = log ?

5

from “The Laws of Logarithms”

log 4 + log 5 = log ?

20

from “The Laws of Logarithms”

Which quotient computes log₇ 20?

log 20 / log 7

from “The Change of Base Rule”

What is log₄ 8, exactly?

3/2

from “The Change of Base Rule”

ln undoes which function?

from “The Natural Logarithm”

What is ln e³?

3

from “The Natural Logarithm”

3^x = 27. What is x?

3

from “Solving Exponential Equations”

2^x = 40. Which expression gives x?

log 40 / log 2

from “Solving Exponential Equations”

What is log₂ 8?

3

from “Logarithmic Graphs”

What is log₁₀ 1000?

3

from “Logarithmic Graphs”

Why take logs of growth data at all?

a line’s rule can be read off

from “Straightening Growth with Logarithms”

On the log plot of y = a · bˣ, what does the slope give?

log b

from “Straightening Growth with Logarithms”

A log-log line has slope 2 and intercept 0.7. Which model fits?

y = 5x²

from “Straightening a Power Law”

On the log-log plot of y = a · xⁿ, what does the slope give?

n

from “Straightening a Power Law”

Plotted against ln x the data give the line y = 5·(ln x) + 6. What is the model?

y = 6 + 5 ln x

from “Fitting a Logarithmic Model”

Values rise forever, but each extra unit of x adds less. Which model?

y = a + b ln x

from “Fitting a Logarithmic Model”

Practice these in the app — your progress saves there.