Chapter 1: Problem 108
Find the reciprocal, or multiplicative inverse, if it exists. $$ -\frac{9}{10} $$
Short Answer
Expert verified
-\frac{10}{9}
Step by step solution
01
Understand the Reciprocal
The reciprocal (or multiplicative inverse) of a number is a value that, when multiplied by the original number, yields 1. For a fraction \(\frac{a}{b}\), the reciprocal is \(\frac{b}{a}\).
02
Identify the Numerator and Denominator
In the given fraction \(-\frac{9}{10}\), identify the numerator \(-9\) and the denominator \10\.
03
Swap the Numerator and Denominator
To find the reciprocal, swap the numerator and the denominator. So, \(-\frac{9}{10}\) becomes \(-\frac{10}{9}\).
04
Simplify the Result (If Needed)
Check if the reciprocal \(-\frac{10}{9}\) can be simplified. In this case, it is already in its simplest form.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Multiplicative inverse
The concept of a multiplicative inverse is key to solving many mathematical problems involving fractions. The multiplicative inverse of a number is simply a value that, when multiplied by the original number, results in 1.
For any fraction \(\frac{a}{b}\), the multiplicative inverse is \(\frac{b}{a}\). This is because when you multiply \(\frac{a}{b}\) by \(\frac{b}{a}\), the \(a\) in the numerator cancels out with the \(a\) in the denominator, and the \(b\) in the denominator cancels out with the \(b\) in the numerator, resulting in 1:
\[ \frac{a}{b} \times \frac{b}{a} = 1 \] In simple terms, the multiplicative inverse is like flipping a fraction upside down. But remember, the sign of the original fraction stays the same. So if you had \(-\frac{9}{10}\), its reciprocal, or multiplicative inverse, would be \(-\frac{10}{9}\).
Learning to find the multiplicative inverse can help you with division involving fractions because dividing by a fraction is the same as multiplying by its reciprocal.
For any fraction \(\frac{a}{b}\), the multiplicative inverse is \(\frac{b}{a}\). This is because when you multiply \(\frac{a}{b}\) by \(\frac{b}{a}\), the \(a\) in the numerator cancels out with the \(a\) in the denominator, and the \(b\) in the denominator cancels out with the \(b\) in the numerator, resulting in 1:
\[ \frac{a}{b} \times \frac{b}{a} = 1 \] In simple terms, the multiplicative inverse is like flipping a fraction upside down. But remember, the sign of the original fraction stays the same. So if you had \(-\frac{9}{10}\), its reciprocal, or multiplicative inverse, would be \(-\frac{10}{9}\).
Learning to find the multiplicative inverse can help you with division involving fractions because dividing by a fraction is the same as multiplying by its reciprocal.
Numerator and denominator
Understanding the parts of a fraction is essential for mastering fractions. A fraction has two main parts: the numerator and the denominator.
The numerator is the top number in a fraction and tells you how many parts you have. For example, in the fraction \(-\frac{9}{10}\), -9 is the numerator. The denominator is the bottom number and tells you how many equal parts make up a whole. In the fraction \(-\frac{9}{10}\), 10 is the denominator.
To find the reciprocal of \(-\frac{9}{10}\), you swap the numerator and the denominator. The numerator becomes 10 and the denominator becomes -9, giving you the fraction \(-\frac{10}{9}\). This transformation is crucial in finding the multiplicative inverse of a fraction.
Remember, knowing which number is the numerator and which is the denominator is the first step in solving fraction-related problems.
The numerator is the top number in a fraction and tells you how many parts you have. For example, in the fraction \(-\frac{9}{10}\), -9 is the numerator. The denominator is the bottom number and tells you how many equal parts make up a whole. In the fraction \(-\frac{9}{10}\), 10 is the denominator.
To find the reciprocal of \(-\frac{9}{10}\), you swap the numerator and the denominator. The numerator becomes 10 and the denominator becomes -9, giving you the fraction \(-\frac{10}{9}\). This transformation is crucial in finding the multiplicative inverse of a fraction.
Remember, knowing which number is the numerator and which is the denominator is the first step in solving fraction-related problems.
Simplifying fractions
After finding the reciprocal of a fraction, it's good practice to check if it can be simplified further. Simplifying a fraction means reducing it to its simplest form, where the numerator and the denominator have no common factors other than 1.
For example, if you have the fraction \(-\frac{10}{9}\), check if there are any common factors between 10 and 9. In this case, 10 and 9 share no common factors other than 1, which means \(-\frac{10}{9}\) is already in its simplest form.
Simplifying fractions can make further calculations easier and the results more understandable. It’s a helpful step in dealing with complex fractions or when you need a clear and concise answer.
To simplify any fraction, follow these steps:
For example, if you have the fraction \(-\frac{10}{9}\), check if there are any common factors between 10 and 9. In this case, 10 and 9 share no common factors other than 1, which means \(-\frac{10}{9}\) is already in its simplest form.
Simplifying fractions can make further calculations easier and the results more understandable. It’s a helpful step in dealing with complex fractions or when you need a clear and concise answer.
To simplify any fraction, follow these steps:
- Find the greatest common divisor (GCD) of the numerator and the denominator.
- Divide both the numerator and the denominator by this GCD.