Chapter 0: Problem 78
Simplify. $$ 8^{2 / 3} $$
Short Answer
Expert verified
The simplified form of \( 8^{2/3} \) is 4.
Step by step solution
01
Understand the Expression
The expression to simplify is \( 8^{2/3} \). This is a fractional exponent, which means we need to understand it as a root and a power.
02
Convert Exponent to Radical Form
A fractional exponent like \( a^{m/n} \) can be understood as either \( (a^m)^{1/n} \) or \( (a^{1/n})^m \). In our case \( 8^{2/3} \) can be rewritten as \( (8^{1/3})^2 \).
03
Find the Cube Root
The cube root of 8 is \( 2 \), because \( 2^3 = 8 \). So, \( 8^{1/3} = 2 \).
04
Square the Result
Now we square the result of the cube root: \( 2^2 = 4 \). Therefore, \( (8^{1/3})^2 = 4 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Simplifying Exponents
Simplifying exponents is like cleaning up a math expression to make it easier to understand or work with. Often, this involves working with fractional exponents. A fractional exponent can look confusing, but it simply represents a combination of taking roots and raising to a power.
- The numerator of the fractional exponent tells you the power to which the base is raised.
- The denominator indicates the root you need to find.
Radical Expressions
A radical expression involves roots, like the square root or the cube root. When you see a fractional exponent such as \(a^{m/n}\), it tells you to use a radical expression.
In the case of \(8^{2/3}\), you can rewrite this as a radical by understanding it as \((8^{1/3})^2\). Here:
In the case of \(8^{2/3}\), you can rewrite this as a radical by understanding it as \((8^{1/3})^2\). Here:
- \(8^{1/3}\) means "the cube root of 8".
- This radical expression is easier to manage and calculate step-by-step.
Cube Root
The cube root is a special type of root that given a number, finds another number which when multiplied by itself three times gives the original number. In mathematical terms, if \(x = y^3\), then \(y\) is the cube root of \(x\).
For the number 8, its cube root is 2 because \(2^3 = 8\). This is denoted as \(8^{1/3} = 2\).
For the number 8, its cube root is 2 because \(2^3 = 8\). This is denoted as \(8^{1/3} = 2\).
- The cube root is particularly useful in simplifying expressions with exponents where the base is a perfect cube.
- Cube roots are often simpler to handle than higher-order roots like the fourth or fifth roots.
Exponentiation
Exponentiation is all about repeating multiplication. It tells you how many times a number, called the base, is multiplied by itself.
In the context of fractional exponents, exponentiation combines with roots. After finding a root, you "exponentiate" by raising the result to a certain power which is indicated by the numerator of the fractional exponent.
For example, after calculating the cube root of 8 as 2, to simplify \(8^{2/3}\), you take 2 and raise it to the power of 2: \(2^2 = 4\). This offers:
In the context of fractional exponents, exponentiation combines with roots. After finding a root, you "exponentiate" by raising the result to a certain power which is indicated by the numerator of the fractional exponent.
For example, after calculating the cube root of 8 as 2, to simplify \(8^{2/3}\), you take 2 and raise it to the power of 2: \(2^2 = 4\). This offers:
- A concise way of simplifying expressions.
- Enables solving equations that are otherwise tough to evaluate directly.