Chapter 2: Problem 4
Determine in each exercise whether or not the function is homogeneous. If it is homogeneous, state the degree of the function. $$ \sqrt{x-y} $$
Short Answer
Expert verified
The function is homogeneous with degree 1/2.
Step by step solution
01
Identify the Function
The given function is \( f(x, y) = \sqrt{x-y} \). We need to determine if this function is homogeneous.
02
Define Homogeneity
A function \( f(x, y) \) is homogeneous of degree \( n \) if for any scalar \( k \), \( f(kx, ky) = k^n f(x, y) \). We will use this definition to test our function.
03
Apply Scalar Transformation
Transform both variables using a scalar \( k \). Substitute into the function: \( f(kx, ky) = \sqrt{kx - ky} \). This simplifies to \( \sqrt{k(x - y)} = \sqrt{k} \cdot \sqrt{x - y} \).
04
Determine Homogeneity
From \( f(kx, ky) = \sqrt{k} \cdot \sqrt{x - y} \), observe that the expression can be written as \( k^{1/2} f(x, y) \). This indicates that the function is homogeneous of degree \( 1/2 \).
05
Conclusion
The function \( \sqrt{x-y} \) is homogeneous, and its degree is \( 1/2 \).
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.
Degree of Homogeneity
Understanding the degree of homogeneity is crucial for analyzing functions. A function's degree of homogeneity tells us how a function behaves when we scale its input variables by a constant factor. This is a useful property when studying phenomena that maintain proportionality or scale invariance.
In mathematical terms, a function \( f(x_1, x_2, \ldots, x_n) \) is said to be homogeneous of degree \( n \) if, for any scalar \( k \), the equation \( f(kx_1, kx_2, \ldots, kx_n) = k^n f(x_1, x_2, \ldots, x_n) \) holds true. Here, \( n \) denotes the degree of homogeneity. Let's think of a simple function \( g(x) = x^3 \). When scaling \( x \) by a factor \( k \), \( g(kx) = (kx)^3 = k^3 x^3 \), illustrating that \( g(x) \) is homogeneous of degree 3.
In the exercise provided, the function \( \sqrt{x-y} \) was determined to be homogeneous of degree \( 1/2 \). This means that if every input is scaled by a factor \( k \), the output scales by \( k^{1/2} \). Recognizing this degree provides insights into the behavior of the function under uniform scaling.
In mathematical terms, a function \( f(x_1, x_2, \ldots, x_n) \) is said to be homogeneous of degree \( n \) if, for any scalar \( k \), the equation \( f(kx_1, kx_2, \ldots, kx_n) = k^n f(x_1, x_2, \ldots, x_n) \) holds true. Here, \( n \) denotes the degree of homogeneity. Let's think of a simple function \( g(x) = x^3 \). When scaling \( x \) by a factor \( k \), \( g(kx) = (kx)^3 = k^3 x^3 \), illustrating that \( g(x) \) is homogeneous of degree 3.
In the exercise provided, the function \( \sqrt{x-y} \) was determined to be homogeneous of degree \( 1/2 \). This means that if every input is scaled by a factor \( k \), the output scales by \( k^{1/2} \). Recognizing this degree provides insights into the behavior of the function under uniform scaling.
Scalar Transformation
Scalar transformation involves altering the inputs of a function by a factor, typically denoted as \( k \). It's essential in determining if a function is homogeneous and what its degree of homogeneity might be. This transformation helps in observing the scaling behavior of a function's output when its inputs are scaled.
Consider the original function \( f(x, y) = \sqrt{x-y} \). Under a scalar transformation, each variable is scaled by \( k \), producing new inputs \( kx \) and \( ky \). The function becomes \( f(kx, ky) = \sqrt{kx - ky} \), which can be rewritten using the distributive property as \( \sqrt{k(x-y)} \).
Scalar transformations are a valuable tool in mathematics, as they allow us to analyze and verify the homogeneity and degree of complex functions like \( \sqrt{x-y} \). By transforming the inputs, we gain insights into how the function behaves under different scales.
Consider the original function \( f(x, y) = \sqrt{x-y} \). Under a scalar transformation, each variable is scaled by \( k \), producing new inputs \( kx \) and \( ky \). The function becomes \( f(kx, ky) = \sqrt{kx - ky} \), which can be rewritten using the distributive property as \( \sqrt{k(x-y)} \).
- This simplifies further to \( \sqrt{k} \cdot \sqrt{x-y} \), indicating that the function is multiplied by \( \sqrt{k} \).
- Through this transformation, it becomes clear how the function's outputs relate to the scale factor \( k \).
Scalar transformations are a valuable tool in mathematics, as they allow us to analyze and verify the homogeneity and degree of complex functions like \( \sqrt{x-y} \). By transforming the inputs, we gain insights into how the function behaves under different scales.
Mathematical Proofs
Mathematical proofs provide a rigorous way to confirm properties like homogeneity. They involve logical reasoning and step-by-step demonstration of a theory or hypothesis.
For the function \( \sqrt{x-y} \), the proof of homogeneity involves:
This proof process is crucial—it not only substantiates the function's properties but also strengthens conceptual understanding. Proofs clarify why certain mathematical statements hold true and provide a structured method to validate assumptions. They're the backbone of mathematics, ensuring everything is derived from foundational principles without ambiguities.
For the function \( \sqrt{x-y} \), the proof of homogeneity involves:
- Identifying the function and the scalar transformation \( f(kx, ky) = \sqrt{k(x-y)} \).
- Simplifying to \( \sqrt{k} \cdot \sqrt{x-y} \), which suggests a scaling pattern.
- Confirming that this scaling matches the form \( k^{1/2} f(x, y) \) aligns with the definition of homogeneity of degree \( 1/2 \).
This proof process is crucial—it not only substantiates the function's properties but also strengthens conceptual understanding. Proofs clarify why certain mathematical statements hold true and provide a structured method to validate assumptions. They're the backbone of mathematics, ensuring everything is derived from foundational principles without ambiguities.