Chapter 1: Problem 4
State the range for the given functions. Graph each function.
$$
f(x)=x^{2},-\frac{1}{2}
Short Answer
Expert verified
The range of \( f(x) = x^2 \) for \(-\frac{1}{2} < x < \frac{1}{2}\) is \( 0 < f(x) < \frac{1}{4} \).
Step by step solution
01
Understand the Function
The function given is \( f(x) = x^2 \). We are tasked with determining the range for this function when the domain is restricted to \(-\frac{1}{2} < x < \frac{1}{2}\). The function \( f(x) = x^2 \) is a standard parabola that opens upwards and is symmetric about the y-axis.
02
Identify the Domain Interval
The domain given is \(-\frac{1}{2} < x < \frac{1}{2}\). This means we only consider the values of \( x \) between \(-\frac{1}{2}\) and \(\frac{1}{2}\), not inclusive of the endpoints.
03
Calculate the Function Values at Boundary of the Domain
Evaluate \( f(x) \) at the endpoints of the domain interval near \(-\frac{1}{2}\) and \(\frac{1}{2}\). This gives us the lowest and highest values that \( f(x) \) can take.- When \( x = -\frac{1}{2} \), \( f(x) = \left(-\frac{1}{2}\right)^2 = \frac{1}{4} \).- When \( x = \frac{1}{2} \), \( f(x) = \left(\frac{1}{2}\right)^2 = \frac{1}{4} \).
04
Analyze the Behavior of the Function within the Interval
Within the interval \(-\frac{1}{2} < x < \frac{1}{2}\), \( x^2 \) takes values starting from just above 0 to just below \( \frac{1}{4} \). This is because squaring a number between -0.5 and 0.5 gives a positive number less than 0.25, with the minimum value closer to 0.
05
Determine the Range
Since \( f(x) = x^2 \) is continuous and increasing on both sides towards \( x = 0 \), the range of \( f(x) \) for \(-\frac{1}{2} < x < \frac{1}{2}\) is \( 0 < f(x) < \frac{1}{4} \). The endpoints are not included because \( x \) never actually reaches \(-\frac{1}{2}\) or \( \frac{1}{2} \) in the open interval.
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.
Parabola
A parabola is a u-shaped curve that can open upwards or downwards. It is the graph of a quadratic function, such as the one given in the problem, \( f(x) = x^2 \). This particular function represents a parabola that opens upwards, meaning it has a minimum point at the vertex. The vertex of \( f(x) = x^2 \) is at the origin (0,0), which is the lowest point on this curve.
Parabolas have certain key features:
Parabolas have certain key features:
- **Vertex**: The turning point of the parabola. For \( f(x) = x^2 \), the vertex is at the origin.
- **Axis of Symmetry**: A vertical line that runs through the vertex, dividing the parabola into two mirror-image halves. For \( f(x) = x^2 \), this line is \( x = 0 \).
- **Direction**: The way the parabola opens. Upwards for positive coefficients of \( x^2 \) and downwards for negative ones.
Open Interval
An open interval specifies a range of values for a variable that does not include the endpoints. In mathematical notation, an open interval is expressed with parentheses, for example, \(-\frac{1}{2} < x < \frac{1}{2}\) in this problem. It includes all numbers between the two endpoints but excludes those endpoints themselves.
Consider this in the context of the function \( f(x) = x^2 \): the domain of \( x \) is restricted to this open interval, meaning \( x \) can be any number close to \(-\frac{1}{2} \) or \( \frac{1}{2} \), but not the endpoints themselves.
Consider this in the context of the function \( f(x) = x^2 \): the domain of \( x \) is restricted to this open interval, meaning \( x \) can be any number close to \(-\frac{1}{2} \) or \( \frac{1}{2} \), but not the endpoints themselves.
- **Open intervals** allow us to analyze the range of function values without including boundary effects from the endpoints.
- The endpoints \( -\frac{1}{2} \) and \( \frac{1}{2} \) are crucial for estimating the boundaries of possible values \( f(x) \) can attain.
- In calculus, they are also important in determining limits and continuity.
Symmetric Function
In mathematics, a function is considered symmetric if its graph is a mirror image across a specific line. For the function \( f(x) = x^2 \), it is symmetric about the y-axis. This means if you were to fold the graph along the y-axis, both sides would align perfectly.
- **Y-axis Symmetry**: A function with this type of symmetry is called an "even function." For these functions, \( f(x) = f(-x) \) for all x in the domain.
- For example, \( f(0.4) = (0.4)^2 = 0.16 \) and \( f(-0.4) = (-0.4)^2 = 0.16 \). This verifies that \( f(x) \) is symmetric about the y-axis.