Unit 4
Glossary
Algebra 2
A number in the complex plane. It can be written as \(a + bi\), where \(a\) and \(b\) are real numbers and \(i^2 = \text-1\).
A function is a rule that takes inputs from one set and assigns them to outputs from another set. Each input is assigned exactly one output.
From an earlier course.
A number on the imaginary number line. It can be written as \(bi\), where \(b\) is a real number and \(i^2 = \text-1\).
An irrational number is a number that is not rational. This means it cannot be expressed as a positive fraction, a negative fraction, or zero. It cannot be written in the form \(\frac{a}{b}\), where \(a\) and \(b\) are integers and \(b \neq 0\).
For example, the numbers \(\pi\) and \(\text{-}\sqrt{2}\) are irrational numbers.
From an earlier course.
A rational number is a number that can be written as a positive fraction, a negative fraction, or zero. It can be written in the form \(\frac{a}{b}\), where \(a\) and \(b\) are integers and \(b \neq 0\).
- 0.7 is a rational number because it can be written as \(\frac{7}{10}\).
- The numbers 0, 3, \(\text{-}\frac{3}{4}\), and 6.7 are all rational numbers.
From an earlier course.