Chapter 0: Problem 61
Evaluate the expression by band. Approximate the answer to the nearest hundredth when appropriate. $$ (-8)^{4 / 3} $$
Short Answer
Expert verified
The expression
\((-8)^{4/3}\) equals 16.
Step by step solution
01
Understand the Expression
The expression \((-8)^{4 / 3}\) involves raising -8 to a fractional exponent. This requires understanding of how to handle negative bases and fractional exponents.
02
Rewrite Using Radical Form
The expression can be rewritten using radical notation: \((-8)^{4/3} = \sqrt[3]{(-8)^4}\). This means we first take the cube root of -8, and then raise the result to the power of 4.
03
Calculate the Cube Root
First calculate \(\sqrt[3]{-8}\). The cube root of -8 is -2, since \((-2) \times (-2) \times (-2) = -8\).
04
Raise to the Power of 4
Next, raise the result from Step 3 to the power of 4: \((-2)^4 = (-2) \times (-2) \times (-2) \times (-2) = 16\).
05
Approximate the Result
Since the expression results in an integer value, the answer does not require approximation beyond the decimal point. The answer is 16.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Negative Bases
When dealing with expressions like \((-8)^{4/3}\), understanding negative bases is crucial. A negative base means that the number being affected is less than zero, and the base value itself has its negative sign included in the calculation of powers.
- If the exponent is an even fraction, the final result will be positive, as multiplying an even number of negative numbers gives a positive number.
- Conversely, if the exponent is an odd fraction, the result will remain negative, as an odd number of negative numbers results in a negative product.
Radical Notation
Radical notation gives us a way to express powers as roots. Here, the expression \((-8)^{4/3}\)can be rewritten in radical form to become \(\sqrt[3]{(-8)^4}\). This transformation helps to simplify our calculation by breaking it into more manageable parts: finding a root followed by exponentiation.
- The denominator of the fraction (3 in this example) tells us which root to take, in this case, the cube root of \(-8\).
- Meanwhile, the numerator (4) indicates the power to which the result should be raised.
Cube Root
The cube root process involves finding a number that, when multiplied by itself three times, equals the original number. This is particularly useful when evaluating expressions with fractional exponents involving cubes, like \(\sqrt[3]{-8}\).
- For \(-8\), we find that \(-2\) is the cube root since \((-2) \times (-2) \times (-2) = -8\).
- Finding cube roots of other negative numbers follows the same principle: identify the number which repeats itself threefold to match the original value.
Integer Values
Working with integer values is another aspect of dealing with expressions like \((-8)^{4/3}\). In the solution, once the cube root is found, the next step is raising it to an integer power.
- An intermediate result from the cube root, \(-2\), is raised to the fourth power: \((-2)^4\).
- The operation \((-2) \times (-2) \times (-2) \times (-2)\) results in an integer value, which in this case, is \(16\).