Solve each equation. In Exercises 11–34, give irrational solutions as decimals correct to the nearest thousandth. In Exercises 35-40, give solutions in exact form. (1/3)x = -3
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 29
Textbook Question
Solve each exponential equation in Exercises 23–48. Express the solution set in terms of natural logarithms or common logarithms. Then use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. 5ex=23
Verified step by step guidance1
Start with the given exponential equation: \$5e^{x} = 23$.
Isolate the exponential expression by dividing both sides of the equation by 5: \(e^{x} = \frac{23}{5}\).
To solve for \(x\), take the natural logarithm (ln) of both sides, since the base of the exponential is \(e\): \(\ln\left(e^{x}\right) = \ln\left(\frac{23}{5}\right)\).
Use the logarithmic identity \(\ln\left(e^{x}\right) = x\) to simplify the left side: \(x = \ln\left(\frac{23}{5}\right)\).
To find a decimal approximation, use a calculator to evaluate \(\ln\left(\frac{23}{5}\right)\) and round the result 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.
Exponential Equations
An exponential equation is one in which the variable appears in the exponent, such as 5e^x = 23. Solving these equations often requires isolating the exponential expression before applying logarithms to solve for the variable.
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Natural Logarithms
The natural logarithm, denoted ln, is the inverse function of the exponential function with base e. It allows us to solve equations involving e^x by rewriting e^x = a as x = ln(a), facilitating the isolation of the variable in the exponent.
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Using Calculators for Decimal Approximations
After expressing the solution in logarithmic form, calculators are used to find decimal approximations. This step involves evaluating logarithms and rounding the result to a specified number of decimal places, such as two decimals, for practical use.
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