๐Ÿ“ˆcollege algebra review

key term - Imaginary number

Definition

An imaginary number is a complex number in which the real part is zero and the imaginary part is non-zero. It is typically written in the form $bi$, where $b$ is a real number and $i$ denotes the imaginary unit, defined as $i = \sqrt{-1}$.

5 Must Know Facts For Your Next Test

  1. Imaginary numbers are used to extend the real number system to solve equations that have no real solutions, such as $x^2 + 1 = 0$.
  2. The basic unit of imaginary numbers is $i$, where $i^2 = -1$.
  3. Any complex number can be written as a sum of a real and an imaginary number: $a + bi$.
  4. Operations with imaginary numbers follow similar rules to those for real numbers but include the additional property that $i^2 = -1$.
  5. Imaginary numbers are plotted on the vertical axis of the complex plane, while real numbers are plotted on the horizontal axis.

Review Questions

"Imaginary number" also found in: