Chapter 10: Problem 4
Es ist \(a^{2}=\left|a^{2}\right|=|a|^{2} ; \sqrt{a^{2}}=|a| \quad(\) nicht \(=a\) )
Short Answer
Expert verified
The expressions given demonstrate how the square and absolute function ensures non-negative real values.
Step by step solution
01
Understanding Absolute Value
The absolute value of a number, denoted by \(|a|\), represents the non-negative value of \(a\). This ensures that any expression involving \(|a|\) will always be zero or positive.
02
Properties of Squares and Absolute Values
For any real number \(a\), it holds that \(a^2 = |a|^2\) because both expressions yield the non-negative value of \(a^2\). This is because squaring a negative is also positive, just as the square of the absolute value is positive.
03
Equality Explanation
The equality \(a^2 = \left|a^2\right| = |a|^2\) holds due to the reason explained above. Squaring any real number whether it is positive, negative or zero results in a non-negative number.
04
Square Root Relation
The square root of \(a^2\) is given by \(\sqrt{a^2} = |a|\). This is because the principal square root function itself always yields a non-negative result, hence the necessity of using \(|a|\) instead of just \(a\), which could be negative.
05
Conclusion of Explanation
Given that \(\sqrt{a^2} = |a| eq a\) reinforces that while squaring and then taking the square root of any \(a\) returns its absolute value, it does not necessarily return \(a\) itself if \(a\) were negative.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Properties of Squares
When we square any real number, the result is always non-negative, regardless of whether the original number was positive or negative. This is because multiplying two negative numbers results in a positive product. So, for a number \( a \), its square \( a^2 \) inherently becomes non-negative.
For example, if \( a = -3 \), then \( a^2 = (-3)^2 = 9 \). This behavior helps simplify expressions because you can always expect a positive result. It aligns with the absolute value squared, \(|a|^2\), since \(|a|\) is always non-negative by definition.
For example, if \( a = -3 \), then \( a^2 = (-3)^2 = 9 \). This behavior helps simplify expressions because you can always expect a positive result. It aligns with the absolute value squared, \(|a|^2\), since \(|a|\) is always non-negative by definition.
Square Root
The square root operation is essentially the inverse of squaring a number. However, taking the square root is a little tricky because it aims to return a value whose square gives the original input.
The square root of a number \( a^2 \) is denoted as \( \sqrt{a^2} \). Here, it becomes clear why the result is typically the absolute value \( |a| \). This is because the square root operation is designed to provide a non-negative result, which corresponds directly to the absolute value rather than potentially negative \( a \).
The square root of a number \( a^2 \) is denoted as \( \sqrt{a^2} \). Here, it becomes clear why the result is typically the absolute value \( |a| \). This is because the square root operation is designed to provide a non-negative result, which corresponds directly to the absolute value rather than potentially negative \( a \).
Non-negative Values
Non-negative values are all values that are either zero or positive. The absolute value of any real number \( a \) is written as \(|a|\), and it is defined to be non-negative.
This means that regardless of whether \( a \) itself was negative, zero, or positive, \(|a|\) will always be zero or greater.
By ensuring that values remain non-negative, these principles simplify mathematical operations and their subsequent results. This plays a significant role, especially when combined with operations like square rooting, which are constrained to non-negative outputs.
This means that regardless of whether \( a \) itself was negative, zero, or positive, \(|a|\) will always be zero or greater.
By ensuring that values remain non-negative, these principles simplify mathematical operations and their subsequent results. This plays a significant role, especially when combined with operations like square rooting, which are constrained to non-negative outputs.
Principal Square Root
The principal square root refers to the non-negative square root of a number. In mathematics, especially when dealing with real numbers, the principal square root is the default choice for solving square root expressions.
For \( a^2 \), the principal square root is \( \sqrt{a^2} = |a| \). This notation emphasizes that whenever we square a number and find its square root, the outcome is the absolute value \( |a| \), ensuring the result is inherently non-negative. This property consistently guides mathematical solutions that require square roots, reflecting the inherent non-negativity of squaring operations and their inverses.
For \( a^2 \), the principal square root is \( \sqrt{a^2} = |a| \). This notation emphasizes that whenever we square a number and find its square root, the outcome is the absolute value \( |a| \), ensuring the result is inherently non-negative. This property consistently guides mathematical solutions that require square roots, reflecting the inherent non-negativity of squaring operations and their inverses.