1.1 Writing Complex Numbers

Solve x2 - 4 = 0 and x2 + 4 = 0

Imaginary Numbers In the real number system, there isn’t a number we can square to get -4. Imaginary numbers: Don’t think of them as “not real” Mathematicians chose this term for the pattern to describe the square root of a negative number after they thought all real numbers were identified

In Real-Life?

Vocabulary Imaginary unit i : i = i2 = Complex number: Imaginary number: Pure imaginary number:

Complex Numbers (a + bi) Standard Form Imaginary Numbers (a + bi, b ≠ 0) Real Numbers (a + 0i) Pure Imaginary Numbers (0 + bi, b ≠ 0)

Write the complex number in standard form. 1. 2. 3. 4.

With a partner, do p. 3 #’s 1-10

Two Equal Complex Numbers Two complex numbers a + bi and c + di are equal if and only if a = ___ and b = ___ Example: Find real numbers x and y to make the equation true. 2x + 2yi = 6 + 4i 3x + 5yi = 9 – 15i

Homework Pg. 4, 1 – 31 odds