Chapter 3: Problem 33
For the following exercises, evaluate or solve, assuming that the function \(f\) is one-to-one. If \(f(6)=7, \mathrm{fi} \mathrm{d} f^{-1}(7)\).
Short Answer
Expert verified
\( f^{-1}(7) = 6 \).
Step by step solution
01
Understanding the Problem
We are given a function \( f \) which is one-to-one, meaning each output is paired with exactly one input. The problem asks us to find the inverse function value \( f^{-1}(7) \), given that \( f(6) = 7 \). An inverse function reverses the roles of inputs and outputs.
02
Identify the Input-Output Pair
Since \( f(6) = 7 \), it means when the input is 6, the output is 7. In the case of an inverse function \( f^{-1} \), we swap the input and output, so \( f^{-1}(7) = 6 \).
03
Verify the Inverse Property
To ensure the inverse is correct, apply the property \( f(f^{-1}(b)) = b \) for any value \( b \). Here, \( f(f^{-1}(7)) = f(6) = 7 \), confirming the inverse function has been correctly identified.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
One-to-One Function
A one-to-one function, also known as an injective function, is a type of function where every output corresponds to exactly one unique input.
This means no two different inputs can have the same output.
To visualize this, consider a simple mapping or pairing system:
This is why, in the given exercise, knowing that \( f \) is one-to-one assures us that the inverse function \( f^{-1} \) will be valid.
This means no two different inputs can have the same output.
To visualize this, consider a simple mapping or pairing system:
- If you have a set of students and a set of lockers, a one-to-one function would ensure that each student gets their own locker, and no locker is shared nor left out.
- In mathematical terms, for a function \( f(x) \), if \( f(a) = f(b) \), then it must be true that \( a = b \).
This is why, in the given exercise, knowing that \( f \) is one-to-one assures us that the inverse function \( f^{-1} \) will be valid.
Function Evaluation
Function evaluation is the process of determining the output of a function when a specific input is given.
In the case of the function \( f(x) \), evaluating the function involves plugging in the input value in place of \( x \) and calculating the corresponding output.
For example:
This is evident in the exercise when we were tasked with finding \( f^{-1}(7) \), which evaluates the function \( f^{-1} \) to give us the input that returned the output of 7 in the original function.
In the case of the function \( f(x) \), evaluating the function involves plugging in the input value in place of \( x \) and calculating the corresponding output.
For example:
- If \( f(6) = 7 \), then upon evaluating \( f \) at \( x = 6 \) we find that the output is 7.
This is evident in the exercise when we were tasked with finding \( f^{-1}(7) \), which evaluates the function \( f^{-1} \) to give us the input that returned the output of 7 in the original function.
Input-Output Pairs
The concept of input-output pairs is central to understanding how functions operate.
Each pair consists of an input \( x \) and a corresponding output \( f(x) \).
In a one-to-one function, each input-output pair is unique:
Each pair consists of an input \( x \) and a corresponding output \( f(x) \).
In a one-to-one function, each input-output pair is unique:
- This guarantees that every input has one specific output, and this pairing does not repeat with different inputs having the same output.
- Where 6 is the input and 7 is the output.
- When finding the inverse function pairs, these roles are reversed, forming the pair \( (7, 6) \), with 7 as the input and 6 as the output.
Inverse Property
The inverse property is a defining feature of inverse functions.
It states that for a function \( f \) and its inverse \( f^{-1} \), the following must hold true:
In the exercise, the inverse property was used to confirm that \( f^{-1}(7) = 6 \):
It states that for a function \( f \) and its inverse \( f^{-1} \), the following must hold true:
- \( f(f^{-1}(x)) = x \)
- \( f^{-1}(f(x)) = x \)
In the exercise, the inverse property was used to confirm that \( f^{-1}(7) = 6 \):
- By checking that \( f(f^{-1}(7)) = f(6) = 7 \), we verify that the correct inverse value was found.
- This property is crucial in ensuring that inverses accurately reverse the original function's operations.