Chapter 10: Problem 83
Use rational expressions to write as a single radical expression. $$ \sqrt[5]{7} \cdot \sqrt[3]{y} $$
Short Answer
Expert verified
\( \sqrt[15]{7^3 \cdot y^5} \)
Step by step solution
01
Convert Radicals to Exponents
The first step involves rewriting each radical expression in terms of exponents. Recall that the nth root of a number can be expressed as that number raised to the power of \( \frac{1}{n} \). So, rewrite \( \sqrt[5]{7} \) as \( 7^{\frac{1}{5}} \) and \( \sqrt[3]{y} \) as \( y^{\frac{1}{3}} \).
02
Multiply the Expressions
Since both expressions are now in exponential form, multiply them together: \( 7^{\frac{1}{5}} \times y^{\frac{1}{3}} \). In exponentiation, multiplication of bases with different exponents keeps the bases separate and maintains their respective exponents.
03
Re-compose as a Single Radical Expression
To express the resulting product as a single radical, recognize that a common expression with a single radical has a unified base. Combine the product under a single radical using the least common multiple (LCM) of the denominators of the fractional exponents. The LCM of 5 and 3 is 15. Thus express the radicals as a single 15th root: \( \sqrt[15]{7^3 \cdot y^5} \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Radicals
Radicals represent the root of a number. They are written using the radical symbol (√). For example, the radical expression \( \sqrt[5]{7} \) is the fifth root of 7. Radicals are a central concept in algebra and are vital for simplifying complex mathematical expressions. Handling radicals involves understanding their properties:
- The nth root of a number means finding a number which, when raised to the nth power, gives you the original number.
- A radical can be converted to an exponent by expressing the nth root as a power of \( \frac{1}{n} \).
Exponents
Exponents are a way to represent repeated multiplication. An expression like \( x^n \) means "x multiplied by itself n times." Let's look at key points about exponents:
- Exponents can be fractions, which ties them to radicals. For instance, \( a^{\frac{1}{n}} \) represents the nth root of a.
- When multiplying expressions with the same base, you add the exponents: \( a^m \times a^n = a^{m+n} \).
- With different bases, each base keeps its own exponent when multiplied: \( a^m \times b^n = a^m b^n \).
Least Common Multiple
The Least Common Multiple (LCM) is a concept within number theory that involves finding the smallest number that two or more numbers can divide into without leaving a remainder. Finding the LCM is essential when working with fractional exponents.Here’s how to find the LCM:
- List the multiples of each number.
- Identify the smallest common multiple.
Multiplying Expressions
Multiplying expressions involves more than just arithmetic; it's about combining terms and simplifying results. When multiplying expressions in exponential form, you might encounter several scenarios:
- Like bases: Add the exponents (e.g., \( x^a \times x^b = x^{a+b} \)).
- Unlike bases: Retain the respective bases and exponents (e.g., \( a^m \times b^n \)).
- Combine using common multiples for fractional exponents (as in creating a unified radical expression).