Chapter 11: Problem 8
For Problems \(1-12\), write each radical in terms of \(i\) and simplify; for example, \(\sqrt{-20}=i \sqrt{20}=i \sqrt{4} \cdot \sqrt{5}=\) \(2 i \sqrt{5}\) $$ \sqrt{-32} $$
Short Answer
Expert verified
The simplified form is \(4i \sqrt{2}\).
Step by step solution
01
Rewrite the Radical in Terms of i
For any negative number under the square root, we can factor out \(-1\) and write \( \sqrt{-n} = \sqrt{-1} \times \sqrt{n}\) which equals \(i \sqrt{n}\) since \(i\) is defined as \( \sqrt{-1}\). So, \( \sqrt{-32} = i \sqrt{32}\).
02
Simplify the Radical
Now, break down \( \sqrt{32}\). First, find the prime factorization of 32, which is \( 32 = 2^5\). Express \( \sqrt{32}\) using these factors: \( \sqrt{32} = \sqrt{4 \times 8} = \sqrt{4} \cdot \sqrt{8}\).
03
Further Simplify Each Factor
Since \( \sqrt{4} = 2 \) and \( \sqrt{8} = \sqrt{4 \times 2} = \sqrt{4} \cdot \sqrt{2} = 2 \sqrt{2}\), further simplify to get: \( \sqrt{32} = 2 \times 2 \sqrt{2} = 4 \sqrt{2}\).
04
Combine Results to Express the Final Answer
Combine all the simplifications to express the original radical: \( \sqrt{-32} = i \times 4 \sqrt{2}\). Therefore, the simplified form of \( \sqrt{-32}\) is \( 4i \sqrt{2}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Imaginary Unit
The imaginary unit, denoted by the symbol \(i\), is a fundamental concept in complex numbers. It is defined as the square root of \(-1\). This might seem perplexing at first since the square of any real number is never negative. Nonetheless, \(i\) serves as a powerful tool in mathematics:
- Expression: The expression \(\sqrt{-1} = i\) allows us to work with the square roots of negative numbers.
- Complex Numbers: Using \(i\), any complex number can be expressed in the form \(a + bi\), where \(a\) and \(b\) are real numbers.
Simplifying Radicals
Simplifying radicals involves reducing a radical expression to its simplest form. This process requires recognizing and separating perfect squares from other factors. Here's how it is typically done:
- Identify Factors: Break down the number under the radical into its prime factors. For example, with 32, we have \(32 = 2^5\).
- Simplify Perfect Squares: Extract perfect squares from the radical. For \(\sqrt{32}\), recognize that \(\sqrt{4} \times \sqrt{8}\) can be simplified as \(2\cdot\sqrt{8}\).
- Further Simplification: Continue simplifying the factors, where \(\sqrt{8}\) can be rewritten as \(\sqrt{4} \cdot \sqrt{2} = 2\sqrt{2}\).
- Combine: Lastly, what we have is \(4\sqrt{2}\), a simplified version of \(\sqrt{32}\).
Prime Factorization of Radicals
Prime factorization is a method used to break a number down into its smallest prime factors, which serves as a foundation for simplifying radicals. Let's explore this process:
- Understanding Prime Factorization: Every integer greater than 1 can be expressed uniquely as a product of prime numbers. For example, \(32 = 2\times2\times2\times2\times2 = 2^5\).
- Application to Radicals: When simplifying radicals, prime factorization helps identify perfect squares. It makes it easier to separate these perfect squares from the radical part, streamlining simplification.
- Simplification Through Factorization: In the case of \(\sqrt{32}\), knowing \(32 = 2^5\) helps us rewrite the expression as \(\sqrt{4} \times \sqrt{8}\), simplifying further into \(4\sqrt{2}\) as demonstrated before.