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Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 3, Problem 51abc

In Exercises 39-52, a. Find an equation for ƒ¯¹(x). b. Graph ƒ and ƒ¯¹(x) in the same rectangular coordinate system. c. Use interval notation to give the domain and the range off and ƒ¯¹. f(x) = ∛x + 1

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Step 1: To find the inverse function ƒ¯¹(x), start by replacing f(x) with y. This gives y = ∛x + 1. Next, swap x and y to reflect the inverse relationship. This results in x = ∛y + 1.
Step 2: Solve for y in terms of x. Subtract 1 from both sides to isolate the cube root term: x - 1 = ∛y. Then, cube both sides to eliminate the cube root: (x - 1)^3 = y. Thus, the inverse function is ƒ¯¹(x) = (x - 1)^3.
Step 3: To graph f(x) = ∛x + 1 and its inverse ƒ¯¹(x) = (x - 1)^3 on the same coordinate system, note that the graph of an inverse function is a reflection of the original function across the line y = x. Plot several points for both functions and ensure symmetry about the line y = x.
Step 4: Determine the domain and range of f(x). The cube root function ∛x is defined for all real numbers, and adding 1 does not restrict the domain. Therefore, the domain of f(x) is (-∞, ∞). The range of f(x) is also (-∞, ∞) because the cube root function can output all real numbers.
Step 5: Determine the domain and range of ƒ¯¹(x). Since the inverse function reflects the domain and range of the original function, the domain of ƒ¯¹(x) is (-∞, ∞), and the range of ƒ¯¹(x) is also (-∞, ∞). Use interval notation to express these results.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Inverse Functions

An inverse function reverses the effect of the original function. If f(x) takes an input x and produces an output y, then the inverse function f¯¹(y) takes y back to x. To find the inverse, we typically swap the roles of x and y in the equation and solve for y. Understanding this concept is crucial for finding f¯¹(x) in the given problem.
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Graphing Functions

Graphing functions involves plotting points on a coordinate system to visualize the relationship between the input (x) and output (f(x)). For the original function f(x) and its inverse f¯¹(x), their graphs will reflect across the line y = x. This symmetry is key to understanding how the two functions relate to each other and aids in accurately graphing both functions.
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Domain and Range

The domain of a function is the set of all possible input values (x-values), while the range is the set of all possible output values (f(x)). For the function f(x) = ∛x + 1, the domain is all real numbers since cube roots are defined for all x, and the range is also all real numbers due to the nature of the cube root function. Understanding domain and range is essential for determining the characteristics of both f and its inverse.
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