Chapter 4: Problem 28
Evaluate each expression. $$ (-4)^{-3} $$
Short Answer
Expert verified
-\(\frac{1}{64}\)
Step by step solution
01
- Understand Negative Exponents
A negative exponent indicates a reciprocal. For any non-zero number \(a\) and positive integer \(n\), \(a^{-n} = \frac{1}{a^n}\).
02
- Apply the Negative Exponent Rule
Given the expression \((-4)^{-3}\), rewrite it using the negative exponent rule: \((-4)^{-3} = \frac{1}{(-4)^3}\).
03
- Calculate the Exponentiation
Calculate \((-4)^3\). This means multiplying \(-4\) by itself three times: \(-4 \times -4 \times -4\).
04
- Perform the Multiplication
First, multiply \(-4\) by \(-4\), which gives 16. Then multiply 16 by \(-4\), resulting in \(-64\). Thus, \((-4)^3 = -64\).
05
- Substitute Back
Substitute \((-4)^3\) back into the expression: \(\frac{1}{-64}\).
06
- Simplify
The expression \(\frac{1}{-64}\) simplifies to \(-\frac{1}{64}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Reciprocal
A crucial concept in understanding negative exponents is the reciprocal. In mathematics, the reciprocal of a number is 1 divided by that number. For instance, the reciprocal of 4 is \(\frac{1}{4}\). If you have \(\frac{1}{4}\), the reciprocal is 4. This concept is vital when dealing with negative exponents.
When you see a negative exponent, like \(-3\), it simply means to take the reciprocal of the base raised to the positive of that exponent. In the case of \((-4)^{-3}\), we rewrite it as \(\frac{1}{(-4)^3}\).
Remember **:
When you see a negative exponent, like \(-3\), it simply means to take the reciprocal of the base raised to the positive of that exponent. In the case of \((-4)^{-3}\), we rewrite it as \(\frac{1}{(-4)^3}\).
Remember **:
- The negative exponent tells you to find the reciprocal.
- Apply the exponentiation to the new form.
Exponentiation
Exponentiation is the process of raising a number to a power. It involves multiplying the base by itself as many times as indicated by the exponent. In the given exercise, we have \((-4)^3\). This means we need to multiply \-4 \times -4 \times -4\). Let's break it down:
By understanding exponentiation, you ensure that you have the correct values to use in further calculations.
- First, multiply \(-4 \times -4 = 16\).
- Next, take that result and multiply by \(-4) again: \(16 \times -4 = -64\).
By understanding exponentiation, you ensure that you have the correct values to use in further calculations.
Simplifying Fractions
After converting the negative exponent to a reciprocal and performing the exponentiation, we often need to simplify the resulting fraction. For instance, after calculating \((-4)^3 = -64\), we get \(\frac{1}{-64}\).
Let's look at simplification steps:
Let's look at simplification steps:
- Identify if the fraction can be reduced: In our example, \(\frac{1}{-64}\) is already in its simplest form.
- Recognize any negative signs: For simplification, this means placing the negative sign correctly. In our case, \(\frac{1}{-64}\) simplifies to \- \frac{1}{64}\.