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Ch. R - Review of Basic Concepts
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 1, Problem 18

Write each root using exponents and evaluate. ∜-256

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1
Recognize that the symbol ∜ represents the fourth root, so the expression ∜-256 can be rewritten using exponents as \((-256)^{\frac{1}{4}}\).
Recall that the fourth root of a number is the same as raising that number to the power of \(\frac{1}{4}\).
Since the base is negative, consider whether the fourth root of a negative number is a real number. The fourth root is an even root, and even roots of negative numbers are not real in the set of real numbers.
If working within the complex numbers, express -256 as \(256 \times (-1)\), and rewrite \((-1)\) using Euler's formula or as \(e^{i\pi}\) to handle the complex root.
Use the property of exponents to write \((-256)^{\frac{1}{4}} = 256^{\frac{1}{4}} \times (-1)^{\frac{1}{4}}\), then evaluate each part separately to find the complex roots.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Radical Expressions and Roots

Radical expressions involve roots such as square roots, cube roots, and fourth roots. The symbol ∜ denotes the fourth root, which means finding a number that, when raised to the power of 4, equals the given value. Understanding how to interpret and manipulate these roots is essential for solving the problem.
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Exponential Form of Roots

Roots can be expressed using fractional exponents, where the nth root of a number is written as that number raised to the power of 1/n. For example, the fourth root of a number is the number raised to the 1/4 power. This form allows easier manipulation and evaluation using exponent rules.
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Evaluating Roots of Negative Numbers

When dealing with even roots (like the fourth root) of negative numbers, the result is not a real number because even powers of real numbers are always non-negative. To evaluate such roots, one must consider complex numbers or recognize that the root is not real, which is important for correctly interpreting the problem.
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