Chapter 2: Problem 43
For the following exercises, solve for the unknown variable. $$ \sqrt{|x|^{2}}=x $$
Short Answer
Expert verified
The solution is \(x \geq 0\).
Step by step solution
01
Recognize the Absolute Value Property
The expression under the square root, \(|x|^2\), simplifies to \(|x|\) because the square of any real number is non-negative and its square root is the absolute value. Thus, the equation becomes \(|x| = x\).
02
Consider the Definition of Absolute Value
The absolute value \(|x|\) means x can either be positive or zero. Hence, \(|x| = x\) implies that \(x\) must be non-negative because only when \(x \geq 0\), \(|x|\) returns the original value of \(x\).
03
Solve for x
Since \(|x| = x\) implies \(x \geq 0\), we can conclude \(x\) must be a non-negative number. To check this condition, it's clear that both sides of the equation are equal only if \(x \leq 0\) results in contradiction (since square roots are non-negative). Hence, \(x\) must be non-negative.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Square Root Property
The Square Root Property is a useful tool in solving equations that involve squared terms. It states that if a squared term equals a number, then the original term is either the positive or negative square root of that number. However, when dealing with absolute value equations like \( \sqrt{|x|^2} = x \), this property helps simplify the equation by eliminating the power and square root. In such cases,
- the squared term \(|x|^2\) simplifies to \(|x|\), because the square of absolute value will be non-negative, and taking the square root of a non-negative number results in its absolute value.
- this simplification into \(|x| = x\) avoids dealing with both positive and negative roots explicitly because absolute values are inherently non-negative.
Solving Equations
Solving equations, especially those involving absolute values and square roots, requires careful handling of the properties involved. In the equation \(\sqrt{|x|^2} = x \), the primary approach is simplification using the Square Root Property. Let's break it down:
- First, recognize the expression \(|x|^2\) under the square root, which simplifies to \(|x|\).
- The equation is transformed from having a square root to a straightforward absolute value equation, \(|x| = x\).
- Use the definition of absolute value, which states \(|x|\) equals \(x\) if \(x\) is positive or zero.
Real Numbers
Real numbers form the basis of comprehending equations like \(\sqrt{|x|^2} = x\). These numbers include all possible values that are either positive, negative, or zero, but here, only the non-negative are significant.
- When considering the simplification \(|x|^2 = |x|\), realize real numbers always yield non-negative squares, crucial to solving this type of equation.
- The equation essentially limits \(x\) to real numbers that satisfy \(x \geq 0\) since only non-negative values fit the absolute value condition \(|x| = x\).
Non-negative Values
Non-negative values are central to the equation \(|x| = x\) derived from \(\sqrt{|x|^2} = x\). Non-negative numbers include zero and all positive numbers. Here's how they fit into solving the equation:
- Absolute values, by definition, are always non-negative, which implies \(x\) must be non-negative to satisfy \(|x| = x\).
- When \(x\) is positive or zero, both sides of the equation align perfectly because \(|x|\) holds no other value than \(x\) itself.
- If \(x\) were negative, it would contradict the absolute value definition because \(|x|\) could not equal a negative \(x\).