Algebra 3/4

Algebra 3/4 delves into advanced algebraic concepts, including polynomial functions, rational expressions, and complex numbers.

Basic Concepts

Complex Numbers

What Are Complex Numbers?

Complex numbers extend our number system to include solutions to equations like \( x^2 + 1 = 0 \). They are in the form:

\[ a + bi \]

where \( a \) and \( b \) are real numbers, and \( i \) is the imaginary unit with the property \( i^2 = -1 \).

Working with Complex Numbers

  • Addition/Subtraction: Combine real parts and imaginary parts separately.
  • Multiplication: Use the distributive property and remember that \( i^2 = -1 \).
  • Conjugates: The conjugate of \( a + bi \) is \( a - bi \), useful for dividing complex numbers.

Visualizing Complex Numbers

Complex numbers can be shown on a plane: the horizontal axis is the real part, and the vertical axis is the imaginary part.

Why Do Complex Numbers Matter?

They're essential for solving certain equations and show up in electronics, engineering, and physics.

Examples

  • \( 3 + 4i \) is a complex number where the real part is 3 and the imaginary part is 4.

  • Multiplying \( (2 + 3i) \) and \( (1 - i) \) gives \( 5 + i \).

In a Nutshell

Complex numbers combine real and imaginary parts to solve equations that real numbers alone can't.