Ch. 1 - Functions

Briggs - Calculus: Early Transcendentals 3rd Edition

Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243Not the one you use?Change textbook

Briggs 3rd Edition

Ch. 1 - Functions

Problem 1.9

Chapter 1, Problem 1.9

Find the inverse of the function ƒ(x) = 2x. Verify that ƒ(ƒ⁻¹(x)) = x and ƒ⁻¹(ƒ(x)) = x .

Verified step by step guidance

Step 1: To find the inverse of the function $ f(x) = 2x $, start by replacing $ f(x) $ with $ y $, so we have $ y = 2x $.

Step 2: Swap $ x $ and $ y $ to find the inverse function. This gives us $ x = 2y $.

Step 3: Solve for $ y $ in terms of $ x $. Divide both sides by 2 to get $ y = \frac{x}{2} $.

Step 4: Replace $ y $ with $ f^{-1}(x) $ to express the inverse function: $ f^{-1}(x) = \frac{x}{2} $.

Step 5: Verify the inverse by checking $ f(f^{-1}(x)) = x $ and $ f^{-1}(f(x)) = x $. Substitute $ f^{-1}(x) $ into $ f(x) $ and vice versa, and simplify to confirm both equal $ x $.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

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

Inverse Functions

An inverse function essentially reverses the effect of the original function. For a function f(x), its inverse f⁻¹(x) satisfies the condition that f(f⁻¹(x)) = x for all x in the domain of f⁻¹, and f⁻¹(f(x)) = x for all x in the domain of f. This means that applying the function and then its inverse returns the original input.

Function Composition

Function composition involves combining two functions to create a new function. If you have two functions f and g, the composition f(g(x)) means you apply g first and then apply f to the result. Understanding composition is crucial for verifying the properties of inverse functions, as it demonstrates how they interact with each other.

Linear Functions

A linear function is a polynomial function of degree one, typically expressed in the form f(x) = mx + b, where m is the slope and b is the y-intercept. In the case of f(x) = 2x, it is a linear function with a slope of 2 and no y-intercept. The simplicity of linear functions makes finding their inverses straightforward, as they are one-to-one and can be easily manipulated algebraically.

Recommended video:

07:17

Linearization

Related Practice

Textbook Question

Properties of logarithms Assume logbx = 0.36, logby= 0.56 and logbz = 0.83 . Evaluate the following expressions.

logb x/y

views

Textbook Question

More composite functions Let ƒ(x) = | x | , g(x)= x² - 4 , F(x) = √x , G(x) = (1)/(x-2) Determine the following composite functions and give their domains.

G o G

views

Textbook Question

Sketch the graph of the inverse of ƒ. <IMAGE>

Textbook Question

Simplify the difference quotient (ƒ(x)-ƒ(a)) / (x-a) for the following functions.

ƒ(x) = 4 - 4x + x²

Textbook Question

How do you obtain the graph of $y=-3f$\left$(x$\right$)$ from the graph of $y=f$\left$(x$\right$)$ ?

Textbook Question

Inverse sines and cosines Evaluate or simplify the following expressions without using a calculator.

cos⁻¹ (- 1/2 )