Problem 58
Question
Use properties of logarithms to condense each logarithmic expression. Write the expression as a single logarithm whose coefficient is \(1 .\) Where possible, evaluate logarithmic expressions without using a calculator. $$ 2 \ln x-\frac{1}{2} \ln y $$
Step-by-Step Solution
Verified Answer
The given expression \(2 \ln x-\frac{1}{2} \ln y\) can be condensed to a single logarithm as \( \ln \left( \frac{x^2}{y^{1/2}} \right) \).
1Step 1: Apply the power rule
The first step is to apply the power rule. The power rule states that the coefficient of a logarithm can become the exponent of the argument. So, the given expression, \(2 \ln x - \frac{1}{2} \ln y\), using the power rule, becomes \( \ln x^2 - \ln y^{1/2} \).
2Step 2: Apply the properties of logarithms for subtraction
Next, we see a difference (or subtraction) between two logarithms - the property for this states that the difference of two logs equates to the log of the quotient of their arguments. So, we can write the expression:\( \ln x^2 - \ln y^{1/2} \) as \( \ln \left( \frac{x^2}{y^{1/2}} \right) \).
3Step 3: Simplify the expression
The last step is to simplify the expression. In this case, as no numerical values are provided for x and y, and there is no further simplification available, \( \ln \left( \frac{x^2}{y^{1/2}} \right) \) would be our final expression.
Key Concepts
Logarithm CondensationPower Rule LogarithmsLogarithmic Expressions
Logarithm Condensation
Understanding logarithm condensation is critical when it comes to simplifying complex logarithmic expressions and making sense of exponential relationships. The process of 'condensing' involves taking multiple logarithmic terms and combining them into a single term. This is particularly helpful when working with equations that require a single logarithmic term.
The power of logarithm condensation is best seen when subtracting or adding logarithmic expressions with the same base. According to the properties of logarithms, you can combine these expressions by converting the addition into multiplication and subtraction into division within the argument of the logarithm.
For instance, in our example, the expression starts with two separate logs, which we can convert into a single term by subtracting their arguments—the result of which is notated as the logarithm of a quotient. This method streamlines the expression and sets the stage for any further algebraic manipulation or for solving the given variables.
The power of logarithm condensation is best seen when subtracting or adding logarithmic expressions with the same base. According to the properties of logarithms, you can combine these expressions by converting the addition into multiplication and subtraction into division within the argument of the logarithm.
For instance, in our example, the expression starts with two separate logs, which we can convert into a single term by subtracting their arguments—the result of which is notated as the logarithm of a quotient. This method streamlines the expression and sets the stage for any further algebraic manipulation or for solving the given variables.
Power Rule Logarithms
When it comes to power rule logarithms, mastery of this rule can dramatically simplify the evaluation of logarithmic expressions. The power rule for logarithms allows you to take the exponent of a logarithm’s argument and express it as a multiple of the logarithm itself. This helps in breaking down complex logarithmic terms into simpler components.
In the problem provided, we applied the power rule by transforming the coefficient of the logarithm into the exponent of its argument. For example, the coefficient '2' in front of the \(\ln x\) became the exponent of 'x', effectively rewriting \(2 \ln x\) as \(\ln x^2\). Similarly, the coefficient \(\frac{1}{2}\) was used to adjust the exponent on 'y', turning \(\frac{1}{2} \ln y\) into \(\ln y^{1/2}\). This is an indispensable technique for condensing logarithmic expressions and should be well understood for deeper engagement with logarithms.
In the problem provided, we applied the power rule by transforming the coefficient of the logarithm into the exponent of its argument. For example, the coefficient '2' in front of the \(\ln x\) became the exponent of 'x', effectively rewriting \(2 \ln x\) as \(\ln x^2\). Similarly, the coefficient \(\frac{1}{2}\) was used to adjust the exponent on 'y', turning \(\frac{1}{2} \ln y\) into \(\ln y^{1/2}\). This is an indispensable technique for condensing logarithmic expressions and should be well understood for deeper engagement with logarithms.
Logarithmic Expressions
Dealing with logarithmic expressions is a common challenge in mathematics, but understanding their properties can unlock the ability to simplify and evaluate them with ease. Logarithmic expressions relate to how many times we must multiply a base number to achieve another number. The properties governing these expressions include the product rule, quotient rule, and power rule, among others.
These properties allow us to navigate between logarithmic and exponential forms, to condense multiple logs into a single one, or to expand a single log into multiple terms—providing flexibility in mathematical problem solving. When you encounter a logarithmic expression, identify if any of these properties can apply to condense, expand, or manipulate it for the task at hand. In the step-by-step solution shown here, you can see how applying these properties allows for the combining and simplification of multiple logs into a coherent, simplified form.
These properties allow us to navigate between logarithmic and exponential forms, to condense multiple logs into a single one, or to expand a single log into multiple terms—providing flexibility in mathematical problem solving. When you encounter a logarithmic expression, identify if any of these properties can apply to condense, expand, or manipulate it for the task at hand. In the step-by-step solution shown here, you can see how applying these properties allows for the combining and simplification of multiple logs into a coherent, simplified form.
Other exercises in this chapter
Problem 57
graph f and g in the same rectangular coordinate system. Then find the point of intersection of the two graphs. $$ f(x)=2^{x}, g(x)=2^{-x} $$
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Solve each logarithmic equation. Be sure to reject any value of \(x\) that is not in the domain of the original logarithmic expressions. Give the exact answer.
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In Exercises \(53-58,\) begin by graphing \(f(x)=\log _{2} x .\) Then use transformations of this graph to graph the given function. What is the vertical asympt
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