Chapter 7: Problem 17
Find the inverse of each function. Then graph the function and its inverse. $$ g(x)=-2 x $$
Short Answer
Expert verified
The inverse function is \( g^{-1}(x) = \frac{-1}{2}x \).
Step by step solution
01
Original Function Observation
The given function is a linear function, which is expressed as a simple linear equation: \( g(x) = -2x \).
02
Replace \(g(x)\) with \(y\)
To make the process of finding the inverse easier, rewrite the function as \( y = -2x \).
03
Swap Variables \(x\) and \(y\)
To find the inverse, we need to switch the roles of \(x\) and \(y\) in the equation. This gives us \( x = -2y \).
04
Solve for \(y\)
Rearrange the equation \( x = -2y \) to solve for \(y\). This involves dividing both sides by \(-2\) to isolate \(y\): \[ y = \frac{-1}{2}x \].
05
Express the Inverse Function
Now express the solution from the previous step as the inverse function. The inverse of \( g(x) = -2x \) is \( g^{-1}(x) = \frac{-1}{2}x \).
06
Graph Both Functions
To graph the functions, plot both the original function \( g(x) = -2x \) and its inverse \( g^{-1}(x) = \frac{-1}{2}x \) on the same coordinate plane. The graph of the original function is a line with a slope of \(-2\) passing through the origin. The graph of the inverse function is a line with a slope of \(-\frac{1}{2}\) also passing through the origin.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding Linear Functions
Linear functions are often represented by the equation \( y = mx + c \), where \( m \) is the slope and \( c \) is the y-intercept. These functions create straight lines when graphed. In the case of the function \( g(x) = -2x \), we can see it follows the form \( y = mx + c \) with \( m = -2 \) and \( c = 0 \). This means:
- The line has a slope of \(-2\).
- The line crosses the y-axis at the origin (0,0), as there's no constant \( c \) added.
Exploring Graphing Functions
Graphing functions helps us visualize mathematical relationships. When graphing \( g(x) = -2x \), we begin by determining its slope and intercept, as discussed.
- The slope \(-2\) indicates the line falls two units vertically for each unit it moves horizontally.
- The line passes through (0,0) since the intercept is 0.
Step-by-Step Solving Equations
Solving equations to find an inverse involves swapping variables and solving for the new dependent variable. For the function \( y = -2x \):
- First, swap \( x \) and \( y \) to get \( x = -2y \).
- Next, solve for \( y \) by dividing both sides by \(-2\), yielding \( y = \frac{-1}{2}x \).