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. e^x=5.7
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 equation. In Exercises 11–34, give irrational solutions as decimals correct to the nearest thousandth. In Exercises 35-40, give solutions in exact form. See Examples 1–4.3(2)^(x-2) + 1 = 100
Verified step by step guidance1
Step 1: Start by isolating the exponential term. Subtract 1 from both sides of the equation to get 3(2)^{x-2} = 99.
Step 2: Divide both sides by 3 to further isolate the exponential term, resulting in (2)^{x-2} = 33.
Step 3: Apply the logarithm to both sides to solve for the exponent. You can use the natural logarithm (ln) or common logarithm (log). For example, ln((2)^{x-2}) = ln(33).
Step 4: Use the logarithmic identity ln(a^b) = b*ln(a) to bring down the exponent: (x-2) * ln(2) = ln(33).
Step 5: Solve for x by dividing both sides by ln(2) and then adding 2 to both sides: x = (ln(33)/ln(2)) + 2.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Exponential Functions
Exponential functions are mathematical expressions in the form f(x) = a * b^(x), where 'a' is a constant, 'b' is the base (a positive real number), and 'x' is the exponent. These functions exhibit rapid growth or decay, depending on the base. Understanding their properties is crucial for solving equations involving exponential terms, as they often require logarithmic manipulation to isolate the variable.
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Logarithms
Logarithms are the inverse operations of exponentiation, allowing us to solve for the exponent in an equation. The logarithm log_b(a) answers the question: 'To what exponent must the base 'b' be raised to produce 'a'?' This concept is essential for solving exponential equations, as it enables us to transform the equation into a linear form, making it easier to isolate the variable.
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Rounding and Decimal Approximation
Rounding is the process of adjusting a number to a specified degree of accuracy, often to make it simpler to work with. In this context, rounding to the nearest thousandth means keeping three decimal places. This concept is important when providing solutions in decimal form, as it ensures that the answers are both precise and manageable, particularly when dealing with irrational numbers that cannot be expressed exactly.
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