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3/22/23 Complex Numbers

3/22/23 Complex Numbers

Assessment

Presentation

Mathematics

10th - 12th Grade

Practice Problem

Hard

CCSS
HSN.CN.A.2, HSN.CN.A.3, HSN.CN.A.1

+1

Standards-aligned

Created by

Kourtney Kukowski

Used 13+ times

FREE Resource

13 Slides • 6 Questions

1

The Set of Complex Numbers

Imaginary Numbers are REAL!

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2

Our idea of the possibilities of numbers was altered this week.

There are more numbers than just the set of Real Numbers that exist.

3

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4

Learning Targets

  • I can multiply complex numbers. 

  • I can identify the complex conjugate of a complex number. 

  • I can simplify a quotient with complex numbers.

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5

Recall: Using the "imaginary" unit in problem-solving.

6

Recall: Adding/Subtracting complex numbers

Nothing too crazy.

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7

Multiple Choice

Recall that the value of  i=1i=\sqrt{-1}   . What is the value of  i2i^2  ?

1

1

2

-1

3

2

4

0

8

Multiple Choice

Simplify the expression: i(i+2)i\left(i+2\right)  

1

i+2ii+2i  

2

1+2i-1+2i  

3

3

9

Multiple Choice

Simplify the expression: i(2i)i\left(2i\right)  

1

2i2i  

2

1+2i-1+2i  

3

-2

10

Important to Remember

11

Multiple Choice

Simplify the expression:
(1+2i)(12i)\left(1+2i\right)\left(1-2i\right)  



Hint: Use the distributive property!

1

14i21-4i^2  

2

22  

3

55  

12

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13

Multiple Choice

Identify the complex conjugate:

1+2i1+2i  

1

1+2i1+2i  

2

12i1-2i  

3

i2i^2  

4

1+2i-1+2i  

14

Multiple Choice

Identify the complex conjugate:

23i2-3i  

1

2+3i2+3i  

2

23i2-3i  

3

i2i^2  

4

23i-2-3i  

15

Why the complex conjugate?

16

Why the complex conjugate?

17

Important Note

Multiplying by the complex conjugate does NOT change the quotient/fraction. It simply creates an equivalent fraction.

18

Let's try one more together

19

Debrief

The Set of Complex Numbers

Imaginary Numbers are REAL!

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