Chapter 5: Problem 40
For the following exercises, find the inverse of the function and graph both the function and its inverse. $$ f(x)=\frac{1}{x^{2}}, x \geq 0 $$
Short Answer
Expert verified
The inverse function is \( f^{-1}(x) = \frac{1}{\sqrt{x}} \), for \( x > 0 \).
Step by step solution
01
Understanding the Function
We have the function \( f(x) = \frac{1}{x^2} \) with the condition \( x \geq 0 \). This means the function is defined for non-negative values of \( x \).
02
Setting Up for Inverse Function
To find the inverse, we start by replacing \( f(x) \, \text{with} \, y \). This gives us \( y = \frac{1}{x^2} \). Our job is to solve for \( x \) in terms of \( y \).
03
Solving for x in Terms of y
Rearrange the equation to express \( x \) in terms of \( y \): \( y = \frac{1}{x^2} \) can be rewritten as \( x^2 = \frac{1}{y} \). Solving for \( x \), we get \( x = \sqrt{\frac{1}{y}} \), and since \( x \geq 0 \), \( x = \frac{1}{\sqrt{y}} \). Thus, the inverse function is \( f^{-1}(y) = \frac{1}{\sqrt{y}} \) for \( y > 0 \).
04
State the Inverse Function
The inverse function is \( f^{-1}(x) = \frac{1}{\sqrt{x}} \), defined for \( x > 0 \).
05
Graphing the Function and Its Inverse
Graph the original function \( y = \frac{1}{x^2} \) and its inverse \( y = \frac{1}{\sqrt{x}} \). The graphs will reflect across the line \( y = x \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Function Transformation
Function transformation involves modifying a function to achieve a desired form. For the function given in the exercise, which is \( f(x) = \frac{1}{x^2} \) for \( x \geq 0 \), transformation plays a key role when finding the inverse function. When working with transformations, keep these points in mind:
- The inverse transformation exchanges the roles of \( x \) and \( y \), essentially flipping the function across the line \( y = x \).
- This specific transformation involves algebraic manipulation, which directly leads to finding the inverse.
- Apply transformations carefully to correctly hold onto any restrictions, such as \( x \geq 0 \) in this exercise.
Graphing Functions
Graphing functions makes abstract mathematical concepts more tangible. When graphing \( f(x) = \frac{1}{x^2} \), it is important to remember:
- The function is only defined for \( x \geq 0 \).
- As \( x \) increases, \( f(x) \) decreases, approaching zero, but never reaching it.
- The graph is a downward opening parabola that is steepest near the origin on the positive side.
To graph the inverse:
- The inverse is defined for \( x > 0 \) and decreases as \( x \) increases.
- Plotting both graphs on the same axes illustrates their reflection symmetry across the line \( y = x \).
- Symmetry confirms the correctness of inverse calculations and provides visual insight into their relationships.
Domain and Range
Understanding the domain and range of a function is essential for graphing both the function and its inverse. For the function \( f(x) = \frac{1}{x^2} \):
- Domain: Since \( x \geq 0 \), the domain is \( [0, \infty) \).
- Range: As \( f(x) \) \( \geq 0 \) for all \( x \), the range is \((0, \infty) \).
- Domain: Since \( x > 0 \), the domain is \( (0, \infty) \).
- Range: The range aligns with the domain of the original function: \( [0, \infty) \).
Calculus
Although the task at hand primarily involves algebraic transformations and graphing, calculus often plays a supporting role. In this context, calculus helps us:
- Analyze the behavior of both the function and its inverse, particularly their limits as they approach endpoints of their domains.
- Confirm that the transformations applied hold true across all required intervals.
- Calculate derivative functions, which can further deepen understanding of the function's behavior, although not explicitly covered here.