/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 62 Solve each logarithmic equation ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

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. $$ 6 \ln (2 x)=30 $$

Short Answer

Expert verified
The exact solution for x is \(\frac{e^5}{2}\) and the decimal approximation, correct to two decimal places, is 67.67.

Step by step solution

01

Simplifying the equation

First, let's divide both sides of the equation by 6 to isolate \(\ln(2x)\) on the left side. This will give us: \(\ln (2 x) = 30 / 6\). Simplifying the right side, we get \(\ln (2 x) = 5\).
02

Converting log equation to exponential form

To solve for \(x\), we need to convert the log equation to an exponential form. Since \(\ln a\) is base \(e\), then \(e^5 = 2x\).
03

Solve for x

In the previous step, we found that \(e^5 = 2x\). Dividing both sides by 2 gives the solution for \(x\). So we have \(x = \frac{e^5}{2}\).
04

Check the solution

The domain of the original logarithmic function \(\ln(2x)\) is \(x > 0\). Since \(\frac{e^5}{2}\) is a positive number, it is part of the domain of the original logarithmic expression, so it is a valid solution.
05

Decimal approximation

Finally, use a calculator to obtain a decimal approximation for the solution, rounded to 2 decimal places. From this, we find that \(x \approx 67.67\).

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Domain of Logarithmic Functions
The domain of a logarithmic function is crucial to understand when solving logarithmic equations. For any logarithm, the argument (the value inside the log) must be greater than zero because the logarithm of a non-positive number is undefined.
Specifically, in our sample problem, the equation given is \(6 \ln(2x) = 30\). The argument of the logarithm function here is \(2x\). Therefore, the domain is defined by the inequality \(2x > 0\), which simplifies to \(x > 0\). This means we are only looking for solutions where \(x\) is positive.
Understanding the domain ensures that the solution we derive from the equation is valid and falls within the acceptable range. Any solution that does not satisfy \(x > 0\) must be rejected.
Exponential Form
Converting a logarithmic equation into its exponential form is a key step in solving for the variable. The natural logarithm, denoted as \(\ln\), is based on the constant \(e\), which is approximately 2.71828.
For any equation of the form \(\ln(a) = b\), this can be rewritten using exponential form as \(a = e^b\).
In our exercise, we had \(\ln(2x) = 5\). By converting to exponential form, we translated it to \(2x = e^5\).
This step is fundamental because it shifts the problem from a logarithmic context to an exponential one, which can often be more straightforward to solve.
Decimal Approximation
After solving the logarithmic equation and ensuring that the solution is within the domain, we often seek a decimal approximation for practical use.
In our case, after solving for \(x\), we found \(x = \frac{e^5}{2}\). To find a useful decimal value, a calculator or computational tool is used.
It's important to know how to correctly approximate this value to the required decimal places. In this instance, we rounded \(x\) to two decimal places resulting in \(x \approx 67.67\).
Decimal approximation makes it easier to interpret the results and apply them in real-world situations, providing a clear image of the result's magnitude.
Solving for x
The process of solving for \(x\) in logarithmic equations involves a few methodical steps. First, isolate the logarithmic term to simplify your equation.
Once the equation is simplified, move the equation into exponential form, as this makes it easier to manipulate algebraically.
In the given task, once we had \(\ln(2x) = 5\), we turned it into \(2x = e^5\). The next step is to solve algebraically for \(x\).
This involves dividing both sides of the equation by 2, giving \(x = \frac{e^5}{2}\). Finally, verify your solution meets the domain's requirements before using any tools for a more precise decimal approximation.
Each step is essential to ensure accuracy and relevance of the answer obtained from the logarithmic equation.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

If \(\$ 4000\) is deposited into an account paying \(3 \%\) interest compounded annually and at the same time \(\$ 2000\) is deposited into an account paying \(5 \%\) interest compounded annually, after how long will the two accounts have the same balance? Round to the nearest year.

Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement. \(\log _{b} x\) is the exponent to which \(b\) must be raised to obtain \(x\).

Hurricanes are one of nature's most destructive forces. These low-pressure areas often have diameters of over 500 miles. The function \(f(x)=0.48 \ln (x+1)+27\) models the barometric air pressure, \(f(x),\) in inches of mercury, at a distance of \(x\) miles from the eye of a hurricane. Use this function to solve Graph the function in a \([0,500,50]\) by \([27,30,1]\) viewing rectangle. What does the shape of the graph indicate about barometric air pressure as the distance from the eye increases?

The figure shows the graph of \(f(x)=\ln x\). Use transformations of this graph to graph each function. Graph and give equations of the asymptotes. Use the graphs to determine each function's domain and range. (GRAPH CANNOT COPY). $$ h(x)=\ln (-x) $$

The figure shows the graph of \(f(x)=\ln x\). Use transformations of this graph to graph each function. Graph and give equations of the asymptotes. Use the graphs to determine each function's domain and range. (GRAPH CANNOT COPY). $$ h(x)=-\ln x $$

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.