/*! 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 11 Find the inverse function of \(f... [FREE SOLUTION] | 91Ó°ÊÓ

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Find the inverse function of \(f\) informally. Verify that \(f\left(f^{-1}(x)\right)=x\) and \(f^{-1}(f(x))=x\). $$f(x)=\sqrt[3]{x}$$

Short Answer

Expert verified
The inverse function of \(f(x) = \sqrt[3]{x}\) is \(f^{-1}(x) = x^3\).

Step by step solution

01

Switch \(x\) and \(y\)

This is done to make \(x\) the subject of the function and to allow solving for \(y\). Here, \(x\) would replace \(\sqrt[3]{x}\) and \(y\) would replace \(x\), producing \(x = \sqrt[3]{y}\).
02

Solve for \(y\)

The cube of both sides is carried out to isolate \(y\). This gives \(x^3 = y\), which based on convention, is usually rewritten in this order: \(y=x^3\). So the inverse function of \(f\), denoted \(f^{-1}(x) = x^3\).
03

Verify \(f\left(f^{-1}(x)\right)=x\)

By substituting \(f^{-1}(x)\) into \(f(x)\), we obtain \(f\left(f^{-1}(x)\right) = \sqrt[3]{(x^3)}= x\). So, indeed, \(f\left(f^{-1}(x)\right)=x\). This confirms that \(f^{-1}(x) = x^3\) is the correct inverse function of \(f\).
04

Verify \(f^{-1}(f(x))=x\)

By substituting \(f(x)\) into \(f^{-1}(x)\), we obtain \(f^{-1}(f(x)) = (\sqrt[3]{x})^3= x\). Therefore, \(f^{-1}(f(x))=x\), which further confirms that \(f^{-1}(x) = x^3\) is indeed the correct inverse function of \(f\).

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Key Concepts

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

Verifying Inverse Functions
To understand the verification of inverse functions, consider two functions, say function 'f' and its inverse 'f-inverse'. The hallmark of inverse functions is that when one function is applied after the other, the result is the identity function. This means they 'undo' each other.

For a function \(f(x)\) and its inverse \(f^{-1}(x)\), you can verify if two functions are indeed inverses of each other by checking that \(f(f^{-1}(x)) = x\) and \(f^{-1}(f(x)) = x\). If both of these conditions are satisfied for all \(x\) in the domain of \(f^{-1}\) and \(f\) respectively, then \(f\) and \(f^{-1}\) are inverse functions.

In the given exercise, the function \(f(x)=\sqrt[3]{x}\) has been inverted to find \(f^{-1}(x)\). To verify the inverse, we substitute \(f^{-1}(x)\) into \(f\) and check if the outcome is \(x\). Similarly, we also substitute \(f(x)\) into \(f^{-1}\) and check for the same outcome. As outlined in the solution steps, this verification confirms that \(f^{-1}(x)=x^3\) is indeed the proper inverse of \(f\).
Cube Root Function
The cube root function is the inverse of the cubic function. For any number \(a\), the cube root of \(a\) is a number \(b\) such that \(b^3 = a\). This relationship is expressed as \(b = \sqrt[3]{a}\).

In our exercise, \(f(x) = \sqrt[3]{x}\) represents the cube root function, which essentially reverses the operation of cubing a number. Cube roots are central in solving equations where the variable is under a cube, especially when finding solutions to volume problems and when dealing with physical quantities that involve cubic units.

The cube root function is also crucial in understanding the properties of inverse functions since it’s the inverse of the cubic function \(x^3\). The graph of a cube root function is symmetrical with respect to the origin, indicating that it is an odd function, with the property that \(f(-x) = -f(x)\). The function also passes the horizontal line test, which implies it has an inverse.
Function Composition
Function composition involves applying one function to the results of another. It is denoted as \(f(g(x))\) or \(g(f(x))\), depending on the order of application. This concept is illustrated when verifying inverse functions, as we apply the inverse to the function and vice versa.

Composition with Inverses

When dealing with inverse functions, function composition helps us to verify that two functions are inverses by observing that \(f(f^{-1}(x))\) and \(f^{-1}(f(x))\) simplify to \(x\). If \(f\) and \(f^{-1}\) are true inverses, composing them in any order should return the original input \(x\).

In the exercise, the function composition \(f(f^{-1}(x)) = \sqrt[3]{(x^3)} = x\) demonstrates how the cube root function and its inverse cancel out, leaving us with the original \(x\). This is the crux of function composition when discussing inverse functions and shows a concrete example of the definition in action.

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