Solve each equation. Give solutions in exact form. log(2 - x) = 0.5
Table of contents
- 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
Solving Exponential and Logarithmic Equations
Problem 49
Textbook Question
Solve each logarithmic equation in Exercises 49–92. Be sure to reject any value of x that is not in the domain of the original logarithmic expressions. Give the exact answer. Then, where necessary, use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. log3x=4
Verified step by step guidance1
Identify the given logarithmic equation: \(\log_{3} x = 4\).
Recall the definition of a logarithm: \(\log_{a} b = c\) means \(a^{c} = b\). Using this, rewrite the equation as \$3^{4} = x$.
Calculate the value of \$3^{4}\( to find \)x$. (You can leave it as an expression for the exact answer.)
Check the domain of the original logarithmic expression. Since \(\log_{3} x\) is defined only for \(x > 0\), ensure your solution satisfies this condition.
If needed, use a calculator to find the decimal approximation of \(x\) to two decimal places.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Definition of Logarithms
A logarithm answers the question: to what exponent must the base be raised to produce a given number? For example, log₃(x) = 4 means 3 raised to the power 4 equals x. Understanding this definition allows you to rewrite logarithmic equations in exponential form to solve for the variable.
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Domain of Logarithmic Functions
The domain of a logarithmic function log_b(x) includes only positive real numbers (x > 0) because logarithms of zero or negative numbers are undefined. When solving logarithmic equations, it is essential to check that solutions fall within this domain to ensure they are valid.
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Exact and Approximate Solutions
Logarithmic equations often yield exact solutions expressed in exponential form. However, when a decimal approximation is required, a calculator can be used to find a numerical value, typically rounded to a specified number of decimal places, such as two decimals for clarity and precision.
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