Chapter 1: Problem 25
For the following exercises, determine whether the relation represents \(y\) as a function of \(x .\) $$y^{2}=x^{2}$$
Short Answer
Expert verified
The relation does not represent \(y\) as a function of \(x\).
Step by step solution
01
Understand the Definition of a Function
A function is a relation where every input (usually denoted as \(x\)) is mapped to exactly one output (usually denoted as \(y\)).
02
Rearrange the Given Equation
Consider the relation \(y^{2} = x^{2}\). Rearrange it to express \(y\) in terms of \(x\). You can rewrite it as \(y = \pm x\).
03
Analyze the Mapping from x to y
For each value of \(x\), there are two possible values for \(y\): \(y = x\) and \(y = -x\).
04
Determine if Multiple Outputs Exist
Since each \(x\) corresponds to two possible \(y\) values, this means that \(y\) is not uniquely determined for every \(x\).
05
Conclude Whether y is a Function of x
Since \(y\) can have more than one value for each \(x\), the relation \(y^2 = x^2\) does not represent \(y\) as a function of \(x\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Relation
In mathematics, a relation describes a connection or association between two sets of numbers or elements. For example, if you have a set of inputs and a set of outputs, a relation tells you how they are related. In simple terms, it's like a rule that links each input to its outputs.
Consider the relation given by the equation \( y^2 = x^2 \). This equation links the variables \( x \) and \( y \).
However, just because there is a relation doesn't automatically mean it's a special one called a function. The word 'relation' itself doesn't imply uniqueness or exclusivity of pairing between inputs and outputs.
Consider the relation given by the equation \( y^2 = x^2 \). This equation links the variables \( x \) and \( y \).
However, just because there is a relation doesn't automatically mean it's a special one called a function. The word 'relation' itself doesn't imply uniqueness or exclusivity of pairing between inputs and outputs.
Input-output Mapping
Input-output mapping refers to how each element from the input set is paired with elements from the output set in a relation. Imagine each \( x \) value as an input you plug in, and the corresponding \( y \) values as the outputs you get.
For the equation \( y^2 = x^2 \), if you try different numbers for \( x \), you'll notice that each input can lead to different outputs.
For the equation \( y^2 = x^2 \), if you try different numbers for \( x \), you'll notice that each input can lead to different outputs.
- For example, if \( x = 3 \), \( y = 3 \) or \( y = -3 \).
- If \( x = -2 \), \( y = 2 \) or \( y = -2 \).
Uniqueness of Outputs
Uniqueness of outputs is a crucial part of defining a function. In a function, every input must relate to one and only one output. This is like saying each key (input) opens exactly one lock (output).
In the equation \( y^2 = x^2 \), for each \( x \) value, there are often two corresponding \( y \) outputs. This breaks the rule of uniqueness, which indicates that our relation isn't a function.
If \( x = 4 \), then \( y \) could be 4 or -4. Such ambiguity in outputs means that the criterion of uniqueness is not met, solidifying the point that the relation is not a function.
In the equation \( y^2 = x^2 \), for each \( x \) value, there are often two corresponding \( y \) outputs. This breaks the rule of uniqueness, which indicates that our relation isn't a function.
If \( x = 4 \), then \( y \) could be 4 or -4. Such ambiguity in outputs means that the criterion of uniqueness is not met, solidifying the point that the relation is not a function.
Functions versus Non-Functions
Understanding the difference between functions and non-functions is essential in grasping how relations work. A function is a particular type of relation where every single input has one distinct output. This is often represented by an arrow pointing from each input to a single output.
- If a relation gives multiple outputs for a single input, like our \( y^2 = x^2 \), it's not a function.
- Consider a function such as \( y = x + 1 \). Here, each \( x \) has one unique \( y \), making it a perfectly valid function.