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91Ó°ÊÓ

If \((5,4)\) is on the graph of the logarithmic function with base \(a\), which of the following statements is true: $$5=\log _{a} 4 \quad \text { or } \quad 4=\log _{a} 5 ?$$

Short Answer

Expert verified
The correct statement is \( \log{_a}{5} = 4 \).

Step by step solution

01

Understanding the given point

The point \( (5, 4) \) lies on the graph of the logarithmic function with base \( a \), meaning that the coordinates satisfy the logarithmic equation in some form.
02

Rewriting the point in logarithmic form

For a logarithmic function, \( (x, y) \) means that \( y = \log{_a}{(x)} \). Here, we have \( (5, 4) \), which implies that \ log{_a}{(5)} = 4 \.
03

Write the final exponential form

The logarithmic equation \( \log{_a}{5} = 4 \) can be rewritten as \( a^4 = 5 \). This confirms the correct form.

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Key Concepts

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

logarithmic equations
Logarithmic equations are essential in mathematics, especially in understanding how to reverse exponential functions. They allow us to solve for unknown variables when the equation involves exponentiation of a particular base. When you see a logarithmic equation, it typically looks like this: \(\text{log}_a(y) = x\). This says that \(a^x = y\).
In logarithmic functions, the base \(a\) must always be greater than 0 and cannot be 1. Understanding the relationship between the coordinates and the function's base helps you translate real-world problems into solvable mathematical equations.
In our exercise, the given point \((5, 4)\) is on the graph of a logarithmic function with base \(a\). This signifies that \(4\) is the logarithm of \(5\) with base \(a\), making our equation \(4 = \text{log}_a (5)\). Once you understand this basic setup, it becomes easier to rewrite the logarithmic form into its exponential counterpart.
exponential form
To solve logarithmic equations, converting them to their exponential form is often useful. This conversion helps to simplify the problem and make it more understandable. The key is to remember that \(\text{log}_a(y) = x\) translates to \(a^x = y\).
Let's use our example: we have \(4 = \text{log}_a (5)\). In exponential form, this means \(a^4 = 5\).
In this equation, \(a\) is the base of the logarithm, \(4\) is the exponent, and \(5\) is the outcome. Understanding this relationship is crucial as it allows you to solve for the variable \(a\) if any two of the three quantities are given.
Converting logarithmic equations to their exponential forms is a powerful tool in algebra and calculus, simplifying complex problems and making them more tractable.
coordinate points
Coordinate points are fundamental in understanding the graph of any function, including logarithmic functions. Typically, a coordinate point \((x, y)\) tells you that \(y\) is the output value of the function when \(x\) is the input.
For logarithmic functions, \((x, y)\) tells us that \(y = \text{log}_a (x)\). Hence, given a point like \((5, 4)\), it tells us that \(4 = \text{log}_a (5)\).
These points are helpful in graphing the function visually, allowing you to see the behavior of the logarithmic curve. The logarithmic function graph features a curve that climbs infinitely but never touches the x-axis. Each point adheres to the equation \( \text{log}_a (x)\) and offers a clear way to understand the transformations and characteristics of the function.
By learning to read and interpret these coordinate points, you can enhance your ability to solve logarithmic equations and understand their real-world applications.

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Most popular questions from this chapter

Medication Effectiveness Drug effectiveness decreases over time. If, each hour, a drug is only \(90 \%\) as effective as the previous hour, at some point the patient will not be receiving enough medication and must receive another dose. If the initial dose was \(200 \mathrm{mg}\) and the drug was administered \(3 \mathrm{hr}\) ago, the expression \(200(0.90)^{3},\) which equals \(145.8,\) represents the amount of effective medication still in the system. (The exponent is equal to the number of hours since the drug was administered.)

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