eolas/Mathematics/Prealgebra/Reciprocals.md
2023-02-10 18:22:04 +00:00

32 lines
1 KiB
Markdown

---
categories:
- Mathematics
tags:
- prealgebra
- fractions
- theorems
---
# Recipricols
The [Property of Multiplicative Identity](Multiplicative%20identity.md) applies to fractions as well as to whole numbers:
$$
\frac{a}{b} \cdot 1 = \frac{a}{b}
$$
With fractions there is a related property: the **Multiplicative Inverse**.
> If $\frac{a}{b}$ is any fraction, the fraction $\frac{b}{a}$ is called the _multiplicative inverse_ or _reciprocol_ of $\frac{a}{b}$. The product of a fraction multiplied by its reciprocol will always be 1. $$ \frac{a}{b} \cdot \frac{b}{a} = 1$$
For example:
$$
\frac{3}{4} \cdot \frac{4}{3} = \frac{12}{12} = 1
$$
In this case $\frac{4}{3}$ is the reciprocol or multiplicative inverse of $\frac{3}{4}$.
This accords with what we know a fraction to be: a representation of an amount that is less than one whole. When we multiply a fraction by its reciprocol, we demonstrate that it makes up one whole.
This also means that whenever we have a whole number $n$, we can represent it fractionally by expressing it as $\frac{n}{1}$