Chapter 6: Problem 45
Use transformations to graph each function. Determine the domain, range, horizontal asymptote, and y-intercept of each function. $$ f(x)=2^{x}+1 $$
Short Answer
Expert verified
Domain: \( (-fty, fty) \). Range: \( (1, fty) \). Horizontal Asymptote: y = 1. Y-intercept: (0, 2).
Step by step solution
01
Understand the parent function
The parent function for this exercise is the exponential function, which is generally written as \[ f(x) = 2^x \]. In this form, the graph of this function passes through the point (0,1), increases rapidly, and has a horizontal asymptote at y=0.
02
Apply the vertical translation
The function given is \[ f(x) = 2^x + 1 \]. This indicates that the graph of the parent function \[ 2^x \] is shifted vertically upwards by 1 unit. This means every point on the graph of \[ 2^x \] will move one unit up.
03
Graph the function
To graph the function \[ f(x) = 2^x + 1 \], start by plotting the key points of the parent function \[ 2^x \], and then shift each point one unit upwards. The new points will include (0, 2), (1, 3), and (-1, 1.5), among others.
04
Determine the domain
The domain of the function \[ f(x) = 2^x + 1 \] is all real numbers because an exponential function is defined for all x. Thus, the domain is \( (-fty, fty) \).
05
Determine the range
Since \[ 2^x \] is always positive and shifts up by 1 unit, the output (range) of \[ 2^x + 1 \] will always be greater than 1. Therefore, the range of the function is \( (1, fty) \).
06
Identify the horizontal asymptote
The horizontal asymptote of the parent function \[ 2^x \] is y = 0. However, shifting this function up by 1 unit changes the horizontal asymptote to y = 1.
07
Find the y-intercept
To find the y-intercept, set \( x = 0 \). \[ f(0) = 2^0 + 1 = 1 + 1 = 2 \]. Therefore, the y-intercept is at the point (0, 2).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
transformations
Transformations help us modify the parent function into a new function by shifting, stretching, or compressing its graph. Here, we focus on vertical translations. The parent function given is an exponential function: \[ f(x) = 2^x \]. This forms the base of our transformations.
When we look at \[ f(x) = 2^x + 1 \], we see that the '+1' term translates the entire graph of \[ 2^x \] one unit upwards.
This is because adding a constant to a function results in shifting the graph vertically. Therefore, every point on \[ 2^x \] moves one unit higher. Understanding transformations like this helps in sketching graphs and predicting their changes accurately.
When we look at \[ f(x) = 2^x + 1 \], we see that the '+1' term translates the entire graph of \[ 2^x \] one unit upwards.
This is because adding a constant to a function results in shifting the graph vertically. Therefore, every point on \[ 2^x \] moves one unit higher. Understanding transformations like this helps in sketching graphs and predicting their changes accurately.
domain
The domain of a function consists of all the input values (x-values) for which the function is defined. In the case of exponential functions like \[ f(x) = 2^x + 1 \], there's no restriction on x.
This means you can plug any real number into the function and get a valid output.
Therefore, the domain remains all real numbers, commonly expressed as \[ (-\fty, \fty) \]. This indicates that the function can take any value of x, from minus infinity to positive infinity.
This means you can plug any real number into the function and get a valid output.
- The exponential function \[ 2^x \] itself is defined for all real numbers.
- The additional '+1' just shifts the output vertically but does not affect the domain.
Therefore, the domain remains all real numbers, commonly expressed as \[ (-\fty, \fty) \]. This indicates that the function can take any value of x, from minus infinity to positive infinity.
range
The range of a function consists of all possible output values (y-values). For \[ f(x) = 2^x + 1 \], the exponential part, \[ 2^x \], always gives positive values. Since we are adding 1 to these values, the output will always be greater than 1.
Therefore, the range excludes 1 but includes every y-value greater than 1.
So, the range of \[ f(x) = 2^x + 1 \] is \[ (1, \fty) \]. This specifies that the function outputs values starting just above 1 and continuing towards infinity.
Therefore, the range excludes 1 but includes every y-value greater than 1.
- Initially, for \[ 2^x \], the range is (0, \[ \fty \]).
- Adding 1 shifts every output up by 1 unit, making the range (1, \[ \fty \]).
So, the range of \[ f(x) = 2^x + 1 \] is \[ (1, \fty) \]. This specifies that the function outputs values starting just above 1 and continuing towards infinity.
horizontal asymptote
To find the horizontal asymptote of an exponential function like \[ f(x) = 2^x + 1 \], observe where the function stabilizes as x approaches infinity or negative infinity.
For the parent function \[ 2^x \], the horizontal asymptote is y = 0 because no matter how large or small x gets, the function never touches y = 0. When we add 1 to this, we shift the entire graph up by 1 unit.
This effectively moves the horizontal asymptote from y = 0 to y = 1.
The horizontal asymptote of \[ f(x) = 2^x + 1 \] is therefore y = 1. This is where the function levels off but never actually reaches.
For the parent function \[ 2^x \], the horizontal asymptote is y = 0 because no matter how large or small x gets, the function never touches y = 0. When we add 1 to this, we shift the entire graph up by 1 unit.
This effectively moves the horizontal asymptote from y = 0 to y = 1.
- For \[ 2^x \], asymptote y = 0.
- After the shift (adding +1), asymptote y = 1.
The horizontal asymptote of \[ f(x) = 2^x + 1 \] is therefore y = 1. This is where the function levels off but never actually reaches.
y-intercept
The y-intercept is the point where the graph crosses the y-axis. To find this, set x to 0 in the function \[ f(x) = 2^x + 1 \].
For \[ x = 0 \], the computation is simple:
\[ f(0) = 2^0 + 1 = 1 + 1 = 2 \].
So, the y-intercept is the point where y equals 2 when x is 0. You can denote this as the coordinate pair (0, 2).
In summary, the y-intercept for \[ f(x) = 2^x + 1 \] is at (0, 2).
For \[ x = 0 \], the computation is simple:
\[ f(0) = 2^0 + 1 = 1 + 1 = 2 \].
So, the y-intercept is the point where y equals 2 when x is 0. You can denote this as the coordinate pair (0, 2).
- The y-intercept shows where the graph begins on the y-axis.
In summary, the y-intercept for \[ f(x) = 2^x + 1 \] is at (0, 2).