Chapter 3

Precalculus · 674 exercises

Problem 1

Explain how to add complex numbers

6 step solution

Problem 2

What is the basic principle in multiplication of complex numbers?

4 step solution

Problem 3

Give an example to show the product of two imaginary numbers is not always imaginary

4 step solution

Problem 4

What is a characteristic of the plot of a real number in the complex plane?

3 step solution

Problem 5

Evaluate the algebraic expressions. If \(f(x)=x^{2}+x-4,\) evaluate \(f(2 i)\)

5 step solution

Problem 6

Evaluate the algebraic expressions. If \(f(x)=x^{3}-2,\) evaluate \(f(i)\)

2 step solution

Problem 7

Evaluate the algebraic expressions. If \(f(x)=x^{2}+3 x+5,\) evaluate \(f(2+i)\)

5 step solution

Problem 8

Evaluate the algebraic expressions. If \(f(x)=2 x^{2}+x-3,\) evaluate \(f(2-3 i)\)

7 step solution

Problem 9

Evaluate the algebraic expressions. If \(f(x)=\frac{x+1}{2-x},\) evaluate \(f(5 i)\)

6 step solution

Problem 10

Evaluate the algebraic expressions. If \(f(x)=\frac{1+2 x}{x+3},\) evaluate \(f(4 i)\)

10 step solution

Problem 13

Plot the complex numbers on the complex plane. \(1-2 i\)

5 step solution

Problem 14

Plot the complex numbers on the complex plane. \(-2+3 i\)

3 step solution

Problem 15

Plot the complex numbers on the complex plane. \(i\)

4 step solution

Problem 16

Plot the complex numbers on the complex plane. \(-3-4 i\)

5 step solution

Problem 17

Perform the indicated operation and express the result as a simplified complex number. \((3+2 i)+(5-3 i)\)

4 step solution

Problem 18

Perform the indicated operation and express the result as a simplified complex number. \((-2-4 i)+(1+6 i)\)

4 step solution

Problem 19

Perform the indicated operation and express the result as a simplified complex number. \((-5+3 i)-(6-i)\)

6 step solution

Problem 20

Perform the indicated operation and express the result as a simplified complex number. \((2-3 i)-(3+2 i)\)

5 step solution

Problem 21

Perform the indicated operation and express the result as a simplified complex number. \((-4+4 i)-(-6+9 i)\)

5 step solution

Problem 22

Perform the indicated operation and express the result as a simplified complex number. \((2+3 i)(4 i)\)

4 step solution

Problem 23

Perform the indicated operation and express the result as a simplified complex number. \((5-2 i)(3 i)\)

4 step solution

Problem 24

For the following exercises, perform the indicated operation and express the result as a simplified complex number \((6-2 i)(5)\)

4 step solution

Problem 25

Perform the indicated operation and express the result as a simplified complex number. \((-2+4 i)(8)\)

5 step solution

Problem 26

Perform the indicated operation and express the result as a simplified complex number. \((2+3 i)(4-i)\)

4 step solution

Problem 27

Perform the indicated operation and express the result as a simplified complex number. \((-1+2 i)(-2+3 i)\)

4 step solution

Problem 28

Perform the indicated operation and express the result as a simplified complex number. \((4-2 i)(4+2 i)\)

5 step solution

Problem 29

Perform the indicated operation and express the result as a simplified complex number. \((3+4 i)(3-4 i)\)

5 step solution

Problem 30

Perform the indicated operation and express the result as a simplified complex number. \(\frac{3+4 i}{2}\)

3 step solution

Problem 31

Perform the indicated operation and express the result as a simplified complex number. \(\frac{6-2 i}{3}\)

4 step solution

Problem 32

Perform the indicated operation and express the result as a simplified complex number. \(\frac{-5+3 i}{2 i}\)

6 step solution

Problem 33

Perform the indicated operation and express the result as a simplified complex number. \(\frac{6+4 i}{i}\)

3 step solution

Problem 34

Perform the indicated operation and express the result as a simplified complex number. \(\frac{2-3 i}{4+3 i}\)

5 step solution

Problem 35

Perform the indicated operation and express the result as a simplified complex number. \(\frac{3+4 i}{2-i}\)

5 step solution

Problem 36

Perform the indicated operation and express the result as a simplified complex number. \(\frac{2+3 i}{2-3 i}\)

5 step solution

Problem 37

Perform the indicated operation and express the result as a simplified complex number. \(\sqrt{-9}+3 \sqrt{-16}\)

3 step solution

Problem 38

Perform the indicated operation and express the result as a simplified complex number. \(-\sqrt{-4}-4 \sqrt{-25}\)

5 step solution

Problem 39

Perform the indicated operation and express the result as a simplified complex number. \(\frac{2+\sqrt{-12}}{2}\)

3 step solution

Problem 40

Perform the indicated operation and express the result as a simplified complex number. \(\frac{4+\sqrt{-20}}{2}\)

4 step solution

Problem 41

Perform the indicated operation and express the result as a simplified complex number. \(i^{8}\)

3 step solution

Problem 42

Perform the indicated operation and express the result as a simplified complex number. \(i^{15}\)

3 step solution

Problem 43

Perform the indicated operation and express the result as a simplified complex number. \(i^{22}\)

4 step solution

Problem 44

Use a calculator to help answer the questions. Evaluate \((1+i)^{k}\) for \(k=4,8,\) and \(12 .\) Predict the value if \(k=16\)

6 step solution

Problem 45

Use a calculator to help answer the questions. Evaluate \((1-i)^{k}\) for \(k=2,6,\) and \(10 .\) Predict the value if \(k=14\)

4 step solution

Problem 46

Use a calculator to help answer the questions. Evaluate \((1+i)^{k}-(1-i)^{k}\) for \(k=4,8,\) and \(12 .\) Predict the value for \(k=16\)

5 step solution

Problem 47

Use a calculator to help answer the questions. Show that a solution of \(x^{6}+1=0\) is \(\frac{\sqrt{3}}{2}+\frac{1}{2} i\)

3 step solution

Problem 48

Use a calculator to help answer the questions. Show that a solution of \(x^{8}-1=0\) is \(\frac{\sqrt{2}}{2}+\frac{\sqrt{2}}{2} i\)

5 step solution

Problem 49

Evaluate the expressions, writing the result as a simplified complex number. \(\frac{1}{i}+\frac{4}{i^{3}}\)

5 step solution

Problem 50

Evaluate the expressions, writing the result as a simplified complex number. \(\frac{1}{i^{11}}-\frac{1}{i^{21}}\)

6 step solution

Problem 51

Evaluate the expressions, writing the result as a simplified complex number. \(i^{7}\left(1+i^{2}\right)\)

4 step solution

Problem 52

Evaluate the expressions, writing the result as a simplified complex number. \(i^{-3}+5 i^{7}\)

4 step solution

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