Chapter 3: Problem 50
Find the inverse function of \(f\). \(f(x)=1-x^{3}\)
Short Answer
Expert verified
The inverse of \( f(x) = 1-x^3 \) is \( f^{-1}(x) = \sqrt[3]{1-x} \).
Step by step solution
01
Understand the Inverse Function
The inverse function of a function \( f \) is a function \( f^{-1} \) such that \( f(f^{-1}(x)) = x \) for every \( x \) in the domain of \( f^{-1} \). In simple terms, the function reverses the effect of \( f \). For our function, \( f(x) = 1 - x^3 \), we need to find \( y = f^{-1}(x) \) such that when we substitute \( y \) into \( f \), we get \( x \).
02
Set Up the Equation
Start with the equation for \( y = f^{-1}(x) \). Substitute \( y \) into the original function: \( x = 1 - y^3 \). This equation expresses \( y \) as a function of \( x \), which we will solve to find our inverse function.
03
Solve for the Inverse
Rearrange the equation \( x = 1 - y^3 \) to solve for \( y \). First, isolate the term \( y^3 \) by subtracting 1 from both sides: \( y^3 = 1 - x \). Then, take the cube root of both sides to solve for \( y \): \( y = \sqrt[3]{1 - x} \).
04
Verify the Inverse Function
To verify our solution, check that \( f(f^{-1}(x)) = x \). Substitute \( y = \sqrt[3]{1-x} \) into the original function: \( f(y) = 1 - (\sqrt[3]{1-x})^3 = 1 - (1-x) = x \). Therefore, \( f(f^{-1}(x)) = x \), confirming that our inverse function is correct.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Functions
Functions are fundamental in mathematics as they define a unique relationship between two sets – often referred to as the domain and the range.
- A function takes an input from the domain and maps it to an output in the range.
- Traditionally written as \( f(x) \), here \( f \) denotes the function and \( x \) represents the input variable.
- The equation describes how to calculate the output from a given input.
Cube Roots
The cube root is an inverse operation of cubing a number, similar to how the square root is the inverse of squaring. It helps us "undo" the process of raising a number to the power of three.
- The cube root of a number \( a \) is a value \( b \) such that \( b^3 = a \).
- It is often denoted by \( \sqrt[3]{a} \).
- Cube roots can be either real or complex, but here we focus on real cube roots.
Verification of Inverse Functions
Verification of inverse functions is a crucial step in determining the correctness of your solution. The process involves checking if applying the original function and its calculated inverse results in no change to the input variable.
- For any function \( f \), its inverse \( f^{-1} \) should satisfy the condition: \( f(f^{-1}(x)) = x \).
- This means if you put the output from the inverse function back into the original function, you should get your starting value \( x \).
- Verification reassures you that both the function and its inverse correctly undo each other's operations.