Chapter 10: Problem 44
Solve each equation. Round to the nearest ten-thousandth. $$ e^{3 x}=4 $$
Short Answer
Expert verified
The solution is approximately \( x = 0.4621 \).
Step by step solution
01
Understand the problem
We are given the equation \( e^{3x} = 4 \) and are tasked with solving for \( x \). The expression involves the natural exponential function \( e \). Our goal is to isolate \( x \) in the equation.
02
Apply the natural logarithm
To isolate \( x \), we take the natural logarithm (ln) of both sides of the equation. This gives us:\[ \ln(e^{3x}) = \ln(4) \]This step uses the property that \( \ln(e^y) = y \).
03
Simplify using logarithmic identities
Using the property \( \ln(e^{3x}) = 3x \), we simplify the left side of the equation to obtain:\[ 3x = \ln(4) \]
04
Solve for x
To solve for \( x \), divide both sides of the equation by 3:\[ x = \frac{\ln(4)}{3} \]Calculate \( \ln(4) \) using a calculator, and then divide by 3 to find \( x \).
05
Calculate and round the result
First, find \( \ln(4) \approx 1.386294361 \). Then, divide by 3 to find \( x \approx 0.46209812 \).Round this result to the nearest ten-thousandth to get \( x \approx 0.4621 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Natural Logarithm
The natural logarithm, often denoted as \( \ln(x) \), is a logarithm with the base \( e \), where \( e \) is an irrational constant approximately equal to 2.71828. The natural logarithm is the inverse of the exponential function.
- Inverse Relationship: This means if \( e^y = x \), then \( \ln(x) = y \).
- Key Property: An important property used in calculations is \( \ln(e^y) = y \). This identity plays a crucial role in simplifying exponential equations, as seen in the original exercise.
Rounding Numbers
Rounding numbers is the process of adjusting the digits of a number to make it simpler, keeping it as close as possible to the original. In mathematics, rounding is used to attain a specified level of precision, which is particularly useful for approximating irrational numbers or when an exact value is unnecessary.
- Precision: The problem requires rounding the result to the nearest ten-thousandth, which has four decimal places.
- Rules: Generally, if the digit following the desired precision level is 5 or higher, we round up. If not, we round down.
Logarithmic Identities
Logarithmic identities are mathematical rules that make it easier to work with logarithms. They simplify expressions and provide a smooth transition from exponential to logarithmic forms. Here are a few important logarithmic identities:
- Power Rule: \( \ln(a^b) = b \cdot \ln(a) \). This rule is instrumental when dealing with powers inside a logarithm.
- Product Rule: \( \ln(a \cdot b) = \ln(a) + \ln(b) \).
- Quotient Rule: \( \ln\left(\frac{a}{b}\right) = \ln(a) - \ln(b) \).