Chapter 11: Problem 38
Write each expression in simplest radical form. If \(a\) radical appears in the denominator, rationalize the denominator. $$\sqrt[9]{-27}$$
Short Answer
Expert verified
\( \sqrt[9]{-27} = \sqrt[3]{-3} \)
Step by step solution
01
Simplify the radical
The expression to simplify is \( \sqrt[9]{-27} \). Notice that -27 can be written as \( (-3)^3 \). We want to express this under a different root if possible.
02
Rewrite under the ninth root
We have \( \sqrt[9]{(-3)^3} \). According to the properties of exponents, \( \sqrt[9]{a^b} = a^{b/9} \). Therefore, \( \sqrt[9]{(-3)^3} = (-3)^{3/9} \).
03
Simplify the exponent
Simplify the exponent \( \frac{3}{9} \), which reduces to \( \frac{1}{3} \). Thus the expression \( (-3)^{3/9} \) simplifies to \( (-3)^{1/3} \).
04
Simplify radical form
The expression \( (-3)^{1/3} \) is equivalent to \( \sqrt[3]{-3} \). Which is the simplest radical form without imaginary numbers.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Rationalizing the Denominator
Rationalizing the denominator is a process used to eliminate radicals from the denominator in a fraction. This technique is essential because having radicals in the denominator is not considered proper mathematical form. A rationalized denominator is one without a radical. Here's a step-by-step approach:
- Identify the radical in the denominator.
- Multiply both the numerator and the denominator by the conjugate if the denominator is a binomial (such as \( \sqrt{a} + \sqrt{b} \)), or simply the radical itself if it is a monomial.
- Apply the distributive property to combine and simplify the terms.
- Simplify the fraction, ensuring there are no radicals in the denominator.
Properties of Exponents
Exponents are powerful tools that allow us to write repeated multiplication in a compact form. They obey several important properties that make simplifying expressions easier. Some key properties of exponents include:
- Product of Powers: \( a^m \cdot a^n = a^{m+n} \)
- Power of a Power: \( (a^m)^n = a^{mn} \)
- Power of a Product: \( (ab)^m = a^m \cdot b^m \)
- Quotient of Powers: \( \frac{a^m}{a^n} = a^{m-n} \) (provided \( a eq 0 \))
- Negative Exponent: \( a^{-m} = \frac{1}{a^m} \)
- Zero Exponent: \( a^0 = 1 \) (assuming \( a eq 0 \))
Radical Expressions
Radical expressions involve roots, such as square roots, cube roots, and other types of roots, denoted by the radical symbol \( \sqrt{} \). Simplifying radical expressions often involves expressing numbers or variables under a radical sign in their simplest form.For example, to simplify \( \sqrt[9]{-27} \), we recognize that \( -27 \) can be written as \( (-3)^3 \). Representing this under a root using properties of exponents, \( \sqrt[9]{(-3)^3} \) becomes \( (-3)^{3/9} \), further simplifying to \( \sqrt[3]{-3} \), which is the simplest radical form.
- Identifying Perfect Powers: Break down numbers into factors to find if a root can be simplified.
- Converting Radicals to Exponents: Using \( a^{m/n} = \sqrt[n]{a^m} \) can make certain calculations more straightforward.
- Combining Radicals: Radicals can be combined through multiplication and division if they have the same index.