Chapter 11: Problem 9
Perform the indicated operations, expressing answers in simplest form with rationalized denominators. $$\sqrt[3]{4} \sqrt[3]{2}$$
Short Answer
Expert verified
\( \sqrt[3]{4} \sqrt[3]{2} = 2 \).
Step by step solution
01
Identify the Problem
We are given the expression \( \sqrt[3]{4} \times \sqrt[3]{2} \) and need to find the result in simplest form.
02
Use the Properties of Radicals
According to the properties of radicals, \( \sqrt[n]{a} \times \sqrt[n]{b} = \sqrt[n]{ab} \). So here, we can write \( \sqrt[3]{4} \times \sqrt[3]{2} = \sqrt[3]{4 \times 2} \).
03
Simplify the Expression
Now, multiply the numbers inside the cube root: \( 4 \times 2 = 8 \), resulting in \( \sqrt[3]{8} \).
04
Further Simplify Using Cube Root Properties
We need to simplify \( \sqrt[3]{8} \). The cube root of 8 is 2 because \( 2^3 = 8 \). Therefore, \( \sqrt[3]{8} = 2 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Properties of Radicals
Radicals are symbols that indicate the root of a number. The most common types are square roots, cube roots, and higher roots. Each type of radical has properties that help in simplifying expressions. Here are some basic properties:
- The product property states that for any non-negative numbers \(a\) and \(b\), and any positive integer \(n\), \( \sqrt[n]{a} \times \sqrt[n]{b} = \sqrt[n]{ab} \). This can simplify expressions by combining the terms under a single radical.
- The quotient property lets us divide the numbers inside the radical: \( \sqrt[n]{\frac{a}{b}} = \frac{\sqrt[n]{a}}{\sqrt[n]{b}} \).
- Radicals can also be manipulated similarly to powers. For instance, \( \sqrt[n]{a^m} = a^{\frac{m}{n}} \), and this can transform under-root problems into easier power problems.
Rationalized Denominators
A rationalized denominator refers to ensuring the denominator of a fraction is a simple, non-radical number. This practice comes from the need to simplify expressions in a way that they are easier to understand or compare.
- For instance, if you have \(\frac{1}{\sqrt{2}}\), you can multiply numerator and denominator by \(\sqrt{2}\) to get \(\frac{\sqrt{2}}{2}\).
- The process involves multiplying by a form of 1, such as \(\frac{\sqrt[n]{b}}{\sqrt[n]{b}}\), effectively ridding the denominator of a radical by making it a rational number.
- This process is useful in further simplifying solutions to ensure they are expressible using integers in the denominator.
Cube Root Properties
The cube root is a specific type of radical, represented by \(\sqrt[3]{a}\), which asks "what number, when multiplied by itself twice, equals \(a\)?" Understanding some properties of cube roots can make solving such problems easier.
- The cube root of a product: For numbers \(a\) and \(b\), \( \sqrt[3]{a \times b} = \sqrt[3]{a} \times \sqrt[3]{b} \). This property allows for the simplification seen in the given problem.
- Cubes and cube roots walk hand-in-hand through expressions like \(2^3 = 8\) meaning \(\sqrt[3]{8} = 2\). Recognizing cube numbers such as 8, 27, 64, helps streamline simplification.
- Unlike square roots, cube roots can be negative because multiplying a negative number by itself three times results in a negative number, e.g., \((-2)^3 = -8\) so \(\sqrt[3]{-8} = -2\).