UNIT 9 LESSON 2

COMPLEX NUMBER

OPERATIONS

COLLEGE PREP

OBJECTIVES

• Add or Subtract complex numbers

• Multiply or divide complex numbers

COMPLEX NUMBERS

Complex Numbers have a real and an imaginary part.

Standard form of a complex number is

𝑎 + 𝑏𝑖where “𝑎” is the real part and “𝑏𝑖” is the imaginary part of

the number.

Ex: 7 + 6𝑖

COMPLEX NUMBERS – ADD, SUBTRACT

Just like polynomials, in order to add and subtract

complex numbers you must combine like terms.

In complex numbers like terms are the real parts and

imaginary parts.

EX: 5 + 3𝑖 + 10 − 12𝑖 = 15 − 9𝑖

Add, Subtract Complex Numbers

1. Write in standard form 𝑎 + 𝑏𝑖

2. Combine like terms

• real combines with real

• imaginary combines with imaginary

3. Simplify if needed

Add, Subtract Complex Numbers

Add or Subtract

A. 2 + 3𝑖 + (−6 + 7𝑖) B. 5 + −36 − (2 − −49)

Add or subtract:(you do)

C. 2 − 3𝑖 + −4 + 3𝑖 D. 6 − 4𝑖 − −3 + 𝑖

E. 8 + 5𝑖 − (10 − 2𝑖) F. 𝑖3 + 𝑖5 + 𝑖17 + 𝑖4

Multiply Complex Numbers

1. Write in standard form 𝑎 + 𝑏𝑖

2. Multiply using standard distribution

3. Simplify if necessary

• REMINDER: 𝑖2 = −1

Multiply Complex Numbers

Multiply

G. −49 ⋅ −4 H. 2𝑖(5 − 3𝑖)

Multiply Complex Numbers

Multiply

I. (5 − 2𝑖)(−1 + 3𝑖) J. (3 + 2𝑖)(3 − 2𝑖)

Multiply Complex Numbers

Multiply

K. 2 − 3𝑖 2 L. 𝑖3 ⋅ 𝑖5 ⋅ 𝑖17 ⋅ 𝑖4

OBJECTIVES

• Add or Subtract complex numbers

• Multiply or divide complex numbers

HOMEWORK

In Class Assignment C9.2

Homework H9.2

EDPuzzle Q9.2