Chapter 5: Problem 82
Evaluate using a calculator. $$ \left(\frac{2}{3}\right)^{-5} $$
Short Answer
Expert verified
The value of \( (\frac{2}{3})^{-5} \) is \ \frac{243}{32} = 7.59375 \.
Step by step solution
01
Understand the expression
We need to evaluate the expression \(\frac{2}{3}\right)^{-5}\). Notice that the exponent is negative, which involves taking the reciprocal of the base.
02
Apply the negative exponent rule
The rule for negative exponents states that \(a^{-n} = \frac{1}{a^{n}}\). Apply this rule to get \(\frac{1}{(\frac{2}{3})^{5}}\).
03
Simplify the fraction within the exponent
Find the reciprocal of \( \frac{2}{3} \), which is \( \frac{3}{2} \). Thus, \(\frac{1}{(\frac{2}{3})^{5}} = (\frac{3}{2})^5\).
04
Calculate the exponentiation
Now raise \( \frac{3}{2} \) to the power of 5. This means calculating \( \frac{3^5}{2^5} \). \(3^5 = 243 \) and \({2^5} = 32\), so \( (\frac{3}{2})^5 = \frac{243}{32}\).
05
Use the calculator for confirmation
Input the fraction \( \frac{243}{32} \) into the calculator to get the decimal form. This should give approximately 7.59375.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Reciprocal
Understanding reciprocals is essential when dealing with negative exponents. A reciprocal is simply the inverse of a number or fraction.
For a fraction, you swap the numerator (top part) with the denominator (bottom part). For example, the reciprocal of \( \frac{2}{3} \) is \( \frac{3}{2} \).
We often find reciprocals when the exponent is negative.
For instance, in the exercise \( \frac{2}{3}^{-5} \), we take the reciprocal of \( \frac{2}{3} \), converting it to \( \frac{3}{2} \). This changes the negative exponent to a positive one, making the expression much simpler to handle.
By turning the negative exponent into a positive one, it becomes easier to perform further calculations.
For a fraction, you swap the numerator (top part) with the denominator (bottom part). For example, the reciprocal of \( \frac{2}{3} \) is \( \frac{3}{2} \).
We often find reciprocals when the exponent is negative.
For instance, in the exercise \( \frac{2}{3}^{-5} \), we take the reciprocal of \( \frac{2}{3} \), converting it to \( \frac{3}{2} \). This changes the negative exponent to a positive one, making the expression much simpler to handle.
By turning the negative exponent into a positive one, it becomes easier to perform further calculations.
Fraction Exponentiation
Fraction exponentiation may seem daunting but is quite straightforward once you grasp the fundamentals. When you raise a fraction to a power, you apply the exponentiation to both the numerator and the denominator independently.
For instance, in our problem, \( \frac{3}{2}^5 \), we raise both 3 and 2 to the power of 5.
This gives us \( \frac{3^5}{2^5} \).
Breaking it down step by step:
For instance, in our problem, \( \frac{3}{2}^5 \), we raise both 3 and 2 to the power of 5.
This gives us \( \frac{3^5}{2^5} \).
Breaking it down step by step:
- Calculate \( 3^5 = 243 \)
- Calculate \( 2^5 = 32 \)
- Combine them back to get \( \frac{243}{32} \)
Simplify Expressions
Simplifying expressions is a crucial part of solving mathematical problems efficiently.
In our exercise, we start with a negative exponent and then simplify by converting to a reciprocal and applying the power rule.
Simplification often involves the following steps:
In our exercise, we start with a negative exponent and then simplify by converting to a reciprocal and applying the power rule.
Simplification often involves the following steps:
- Identify and apply exponent rules, such as changing a negative exponent to a positive one by taking the reciprocal.
- Perform the necessary calculations for exponentiation.
- Combine terms to finalize your result.
- Taking the reciprocal to get \( \frac{3}{2} \).
- Raising it to the power of 5 to get \( \frac{3^5}{2^5} \)
- Simplifying to \( \frac{243}{32} \)