Chapter 1: Problem 73
Since \(f(x)\) is an odd function, $$ \left[\frac{x^{2}}{a}\right]=0 \text { for all } x \in[-10,10] $$ or \(0 \leq \frac{x^{2}}{a}<1\) for all \(x \in[-10,10]\) or \(a>100\)
Short Answer
Expert verified
The solution requires \( a > 100 \).
Step by step solution
01
Understand the Properties of an Odd Function
An odd function, by definition, satisfies the property that \( f(-x) = -f(x) \) for all \( x \). This means the graph of \( f(x) \) is symmetric with respect to the origin.
02
Interpreting the Floor Function Condition
The expression \( \left[\frac{x^2}{a}\right]=0 \) means that the greatest integer less than or equal to \( \frac{x^2}{a} \) is 0. Hence, \( 0 \leq \frac{x^2}{a} < 1 \) must hold for all \( x \) in the interval \([-10, 10]\).
03
Exploring the Range of \( x^2 \)
For \( x \) in the range \([-10,10]\), \( x^2 \) varies from \( 0 \) to \( 100 \). Thus, to satisfy the condition \( 0 \leq \frac{x^2}{a} < 1 \), we can say \( \frac{100}{a} < 1 \).
04
Solving Inequality for a
The inequality \( \frac{100}{a} < 1 \) simplifies to \( 100 < a \). Therefore, for the floor function condition to hold, \( a > 100 \).
05
Analyzing Alternative Condition
The problem also allows for the case where \( a > 100 \). Since this directly matches the conclusion from Step 4, \( a>100 \) is indeed a solution.
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.
Understanding the Floor Function
The floor function is a mathematical concept that assigns the largest integer less than or equal to a given number. In notation, it is represented by brackets, like this: \( \left\lfloor x \right\rfloor \). For example, \( \left\lfloor 3.7 \right\rfloor = 3 \) and \( \left\lfloor -2.1 \right\rfloor = -3 \). It's a tool particularly useful in rounding numbers down.
In the context of our problem, when we say \( \left[\frac{x^2}{a}\right] = 0 \), we mean that \(\frac{x^2}{a}\) must be at least 0 and less than 1 for all \(x\) in the interval \([-10, 10]\). This is because the floor function outputs the largest integer, which in this case is zero.
In the context of our problem, when we say \( \left[\frac{x^2}{a}\right] = 0 \), we mean that \(\frac{x^2}{a}\) must be at least 0 and less than 1 for all \(x\) in the interval \([-10, 10]\). This is because the floor function outputs the largest integer, which in this case is zero.
- This implies \(0 \leq \frac{x^2}{a} < 1\)
- It helps us understand the constraints needed for the output to remain non-negative and less than 1
Symmetry with Respect to the Origin
An odd function displays a unique property of symmetry. This means that for any function \(f(x)\), if it is odd, \(f(-x) = -f(x)\). Analytically, this indicates that the function behaves in a mirror-like way, one side perfectly balancing the other when flipped over the origin.
For graphing, symmetry with respect to the origin looks like:
For graphing, symmetry with respect to the origin looks like:
- Points \((x, f(x))\) on the graph will reflect to another point \((-x, -f(x))\)
Exploring Properties of Inequalities
Inequalities help us classify and define ranges of possible values for variables. When stating an inequality, such as \(\frac{100}{a} < 1\), it is critical to understand what this implies.
To solve it: multiply both sides by \(a\), yielding \(100 < a\). This means that \(a\) must be greater than 100 for the condition to hold true.
To solve it: multiply both sides by \(a\), yielding \(100 < a\). This means that \(a\) must be greater than 100 for the condition to hold true.
- Multiplying or dividing by a positive number maintains the inequality direction
- Working through problems like this ensures the mathematical consistency of solutions
Strategies for Mathematical Problem Solving
In mathematics, problem-solving is often a blend of various strategies. You start by understanding the problem itself, identifying what is given, and what needs to be determined.
The steps we undertook follow these logical methods:
The steps we undertook follow these logical methods:
- Identifying key properties, like those of odd functions and floor functions
- Translating complex expressions into inequalities
- Applying algebraic manipulation to deduce unknowns, such as solving \(100 < a\)