Chapter 5: Problem 50
Evaluate each expression. $$r^{2} \div s^{2} \text { if } r=-\frac{3}{4} \text { and } s=1 \frac{1}{3}$$
Short Answer
Expert verified
The expression evaluates to \( \frac{81}{256} \).
Step by step solution
01
Substitute the Values
First, substitute the given values of \( r \) and \( s \) into the expression. We have \( r = -\frac{3}{4} \) and \( s = 1 \frac{1}{3} \). Substitute these into the expression: \( \left(-\frac{3}{4}\right)^{2} \div \left(1 \frac{1}{3}\right)^{2} \).
02
Simplify \( s \) into an Improper Fraction
Convert the mixed number \( s = 1 \frac{1}{3} \) into an improper fraction. \( 1 \frac{1}{3} = \frac{3 \times 1 + 1}{3} = \frac{4}{3} \). Now the expression becomes \( \left(-\frac{3}{4}\right)^{2} \div \left(\frac{4}{3}\right)^{2} \).
03
Calculate \( r^{2} \)
Find the square of \( r \). We have \( r = -\frac{3}{4} \), so \( \left(-\frac{3}{4}\right)^{2} = \frac{(-3)^{2}}{4^{2}} = \frac{9}{16} \).
04
Calculate \( s^{2} \)
Find the square of \( s \). We have \( s = \frac{4}{3} \), so \( \left(\frac{4}{3}\right)^{2} = \frac{4^{2}}{3^{2}} = \frac{16}{9} \).
05
Calculate the Division
Now perform the division: \( \frac{9}{16} \div \frac{16}{9} \). Dividing by a fraction involves multiplying by its reciprocal. Thus, \( \frac{9}{16} \div \frac{16}{9} = \frac{9}{16} \times \frac{9}{16} = \frac{81}{256} \).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Fraction Manipulation
Fraction manipulation is a skill that helps in working with parts of a whole or representing numbers out of a particular total. This involves several sub-skills:
- Simplifying: Fractions can often be simplified by dividing the numerator and the denominator by their greatest common divisor.
- Converting: Mixed numbers need to be converted to improper fractions to simplify calculations. For instance, converting a number like \(1 \frac{1}{3}\) into \(\frac{4}{3}\) ensures uniformity in mathematical operations.
- Rewriting: Operations often require rewriting fractions. For example, converting multiplication or division into straightforward expressions makes them easier to handle.
Exponentiation
Exponentiation is a mathematical process where a number is multiplied by itself a certain number of times. This exercise asks us to understand exponentiation involving fractions:
- Squaring: Squaring a number involves multiplying it by itself. For instance, \(r^2\), where \(r = -\frac{3}{4}\), means \((-\frac{3}{4}) \times (-\frac{3}{4}) = \frac{9}{16}\).
- Fraction Exponentiation: When exponents apply to fractions, apply the power to both the numerator and the denominator separately. For example, \(\left(\frac{4}{3}\right)^2 = \frac{4^2}{3^2} = \frac{16}{9}\).
Division of Fractions
Dividing fractions may sound complex, but a simple rule makes it straightforward: invert and multiply.
- Reciprocal Understanding: To divide by a fraction, multiply by its reciprocal. The reciprocal of \(\frac{16}{9}\) is \(\frac{9}{16}\).
- Applying the Rule: If our goal is to compute \(\frac{9}{16} \div \frac{16}{9}\), convert this to \(\frac{9}{16} \times \frac{9}{16}\).
- Multiplication: Multiply the numerators together and the denominators together, getting \(\frac{81}{256}\).