Logarithmic Function Context and Data Modeling - AP Precalculus
Card 1 of 30
What is the natural logarithm of $e$?
What is the natural logarithm of $e$?
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$1$. $\text{ln}(e) = 1$ by definition of natural logarithm.
$1$. $\text{ln}(e) = 1$ by definition of natural logarithm.
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Identify the domain of $f(x) = \text{log}_b(x)$.
Identify the domain of $f(x) = \text{log}_b(x)$.
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$x > 0$. Logarithm is undefined for non-positive values.
$x > 0$. Logarithm is undefined for non-positive values.
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Find the value of $\text{log}_4(16)$.
Find the value of $\text{log}_4(16)$.
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$2$. $4^2 = 16$, so the answer is 2.
$2$. $4^2 = 16$, so the answer is 2.
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What is the natural logarithm of $e$?
What is the natural logarithm of $e$?
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$1$. $\text{ln}(e) = 1$ by definition of natural logarithm.
$1$. $\text{ln}(e) = 1$ by definition of natural logarithm.
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Simplify $e^{\text{ln}(x)}$.
Simplify $e^{\text{ln}(x)}$.
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$x$. Exponential and natural log cancel as inverses.
$x$. Exponential and natural log cancel as inverses.
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What is the base of a logarithm if $\text{log}_b(100) = 2$?
What is the base of a logarithm if $\text{log}_b(100) = 2$?
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$b = 10$. $10^2 = 100$, so base is 10.
$b = 10$. $10^2 = 100$, so base is 10.
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Express $\text{ln}(e^x)$ in terms of $x$.
Express $\text{ln}(e^x)$ in terms of $x$.
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$x$. Natural log and exponential cancel as inverses.
$x$. Natural log and exponential cancel as inverses.
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Find the value of $\text{log}_7(1)$.
Find the value of $\text{log}_7(1)$.
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$0$. Any base raised to power 0 equals 1.
$0$. Any base raised to power 0 equals 1.
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What is the horizontal asymptote of $f(x) = b^x$?
What is the horizontal asymptote of $f(x) = b^x$?
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$y = 0$. Exponential functions approach zero as $x \to -\infty$.
$y = 0$. Exponential functions approach zero as $x \to -\infty$.
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Identify the vertical asymptote of $f(x) = \text{log}_b(x)$.
Identify the vertical asymptote of $f(x) = \text{log}_b(x)$.
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$x = 0$. Logarithmic functions approach $-\infty$ as $x \to 0^+$.
$x = 0$. Logarithmic functions approach $-\infty$ as $x \to 0^+$.
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State the base of the natural logarithm.
State the base of the natural logarithm.
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$e$. Natural logarithm uses Euler's number as base.
$e$. Natural logarithm uses Euler's number as base.
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State the base of the common logarithm.
State the base of the common logarithm.
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$10$. Common logarithm uses base 10 by convention.
$10$. Common logarithm uses base 10 by convention.
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Evaluate $\text{log}_b(0.01)$ for $b = 10$.
Evaluate $\text{log}_b(0.01)$ for $b = 10$.
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$-2$. $10^{-2} = 0.01$, so the answer is -2.
$-2$. $10^{-2} = 0.01$, so the answer is -2.
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Convert $y = \text{log}_b(x)$ to exponential form.
Convert $y = \text{log}_b(x)$ to exponential form.
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$b^y = x$. Logarithmic and exponential forms are equivalent.
$b^y = x$. Logarithmic and exponential forms are equivalent.
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What is the value of $\text{log}_b(b)$?
What is the value of $\text{log}_b(b)$?
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$1$. Any base raised to the power 1 equals the base.
$1$. Any base raised to the power 1 equals the base.
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Find the value of $\text{log}_3(27)$.
Find the value of $\text{log}_3(27)$.
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$3$. $3^3 = 27$, so the answer is 3.
$3$. $3^3 = 27$, so the answer is 3.
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What is the range of $f(x) = \text{log}_b(x)$?
What is the range of $f(x) = \text{log}_b(x)$?
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All real numbers. Logarithmic functions can output any real value.
All real numbers. Logarithmic functions can output any real value.
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Express $\text{ln}(e^x)$ in terms of $x$.
Express $\text{ln}(e^x)$ in terms of $x$.
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$x$. Natural log and exponential cancel as inverses.
$x$. Natural log and exponential cancel as inverses.
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What is $\text{log}_b(xy)$ in terms of $x$ and $y$?
What is $\text{log}_b(xy)$ in terms of $x$ and $y$?
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$\text{log}_b(x) + \text{log}_b(y)$. Product rule: log of product equals sum of logs.
$\text{log}_b(x) + \text{log}_b(y)$. Product rule: log of product equals sum of logs.
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What is the horizontal asymptote of $f(x) = b^x$?
What is the horizontal asymptote of $f(x) = b^x$?
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$y = 0$. Exponential functions approach zero as $x \to -\infty$.
$y = 0$. Exponential functions approach zero as $x \to -\infty$.
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Identify the vertical asymptote of $f(x) = \text{log}_b(x)$.
Identify the vertical asymptote of $f(x) = \text{log}_b(x)$.
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$x = 0$. Logarithmic functions approach $-\infty$ as $x \to 0^+$.
$x = 0$. Logarithmic functions approach $-\infty$ as $x \to 0^+$.
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Find the value of $\text{log}_7(1)$.
Find the value of $\text{log}_7(1)$.
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$0$. Any base raised to power 0 equals 1.
$0$. Any base raised to power 0 equals 1.
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Convert $\text{log}_b(x) = y$ to its exponential form.
Convert $\text{log}_b(x) = y$ to its exponential form.
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$b^y = x$. Standard form showing logarithm-exponential relationship.
$b^y = x$. Standard form showing logarithm-exponential relationship.
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What is $\text{log}_b(b^{-1})$?
What is $\text{log}_b(b^{-1})$?
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$-1$. Since $b^{-1} = \frac{1}{b}$, the log equals -1.
$-1$. Since $b^{-1} = \frac{1}{b}$, the log equals -1.
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What is the value of $\text{log}_2(32)$?
What is the value of $\text{log}_2(32)$?
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$5$. $2^5 = 32$, so the answer is 5.
$5$. $2^5 = 32$, so the answer is 5.
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Express $\text{log}_b(\frac{1}{x})$ in terms of $x$.
Express $\text{log}_b(\frac{1}{x})$ in terms of $x$.
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$-\text{log}_b(x)$. Using the property $\text{log}_b(x^{-1}) = -\text{log}_b(x)$.
$-\text{log}_b(x)$. Using the property $\text{log}_b(x^{-1}) = -\text{log}_b(x)$.
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What is the base of a logarithm if $\text{log}_b(100) = 2$?
What is the base of a logarithm if $\text{log}_b(100) = 2$?
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$b = 10$. $10^2 = 100$, so base is 10.
$b = 10$. $10^2 = 100$, so base is 10.
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Find the value of $\text{log}_3(27)$.
Find the value of $\text{log}_3(27)$.
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$3$. $3^3 = 27$, so the answer is 3.
$3$. $3^3 = 27$, so the answer is 3.
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What is the exponential form of $\text{ln}(x) = y$?
What is the exponential form of $\text{ln}(x) = y$?
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$e^y = x$. Natural log uses base $e$ in exponential form.
$e^y = x$. Natural log uses base $e$ in exponential form.
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If $b^y = x$, what is $\text{log}_b(x)$?
If $b^y = x$, what is $\text{log}_b(x)$?
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$y$. By definition of logarithm from exponential form.
$y$. By definition of logarithm from exponential form.
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