Use the various properties of exponential and logarithmic functions to evaluate the expressions in parts (a)–(c). Given ƒ(x) = 3x, find ƒ(log3 (2 ln 3))
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- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
6. Exponential & Logarithmic Functions
Properties of Logarithms
Problem 97
Textbook Question
Determine whether each equation is true or false. Where possible, show work to support your conclusion. If the statement is false, make the necessary change(s) to produce a true statement. log(x + 3) - log(2x) = [log(x + 3)/log(2x)]
Verified step by step guidance1
Recall the logarithmic property that states: \(\log a - \log b = \log \left( \frac{a}{b} \right)\), which means the difference of two logs with the same base is the log of the quotient.
Apply this property to the left side of the equation: \(\log(x + 3) - \log(2x) = \log \left( \frac{x + 3}{2x} \right)\).
Examine the right side of the equation: \(\frac{\log(x + 3)}{\log(2x)}\). This expression represents the quotient of two logarithms, which is not equivalent to the difference of the logarithms.
Since \(\log \left( \frac{x + 3}{2x} \right)\) is not equal to \(\frac{\log(x + 3)}{\log(2x)}\), the original equation is false as stated.
To make the equation true, replace the right side with \(\log \left( \frac{x + 3}{2x} \right)\), so the corrected equation is: \(\log(x + 3) - \log(2x) = \log \left( \frac{x + 3}{2x} \right)\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Properties of Logarithms
Logarithmic properties include rules like the product, quotient, and power rules. For example, the difference of two logs with the same base, log(a) - log(b), equals log(a/b). Understanding these properties helps simplify and manipulate logarithmic expressions correctly.
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Change of Base Property
Logarithmic Equality and Expressions
An equation involving logarithms is true only if both sides represent the same value. Recognizing the difference between subtraction of logs and division of logs is crucial, as log(a) - log(b) is not the same as log(a)/log(b). This distinction is key to verifying or correcting logarithmic statements.
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Logarithms Introduction
Domain of Logarithmic Functions
The domain of a logarithmic function includes all positive arguments since log(x) is undefined for x ≤ 0. When working with expressions like log(x + 3) and log(2x), it is essential to ensure x + 3 > 0 and 2x > 0 to maintain valid inputs and avoid extraneous solutions.
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Graphs of Logarithmic Functions
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