Lesson Example Discussion Quiz: Class Homework |
Step-3 |
Title: Division of complex numbers |
Grade: 8-b Lesson: S2-L7 |
Explanation: Hello Students, time to practice and review the steps for the problem. |
Lesson Steps
Step | Type | Explanation | Answer |
---|---|---|---|
1 |
Problem |
Divide \$(5 + 7i)/(3 - 4i)\$ and simplify the result. |
|
2 |
Step |
Given that |
\$(5 + 7i)/(3 - 4i)\$ |
3 |
Step |
Identify the complex conjugate of the denominator: |
The complex conjugate of (3 - 4i) is (3 + 4i) |
4 |
Step |
Multiply both the numerator and denominator by the complex conjugate: |
\$((5 + 7i)(3 + 4i)) / ((3 - 4i)(3 + 4i))\$ |
5 |
Step |
Expand the numerator: |
\$ (5 \times 3) + (5 \times 4i) + (7i \times 3) + (7i \times 4i) \$ \$15 + 20i + 21i + 28i^2\$ 15 + 41i - 28 (since \$i^2 = -1\$) -13 + 41i |
6 |
Step |
Expand the denominator: |
\$(3 \times 3) + (3 \times 4i) + (-4i \times 3) + (-4i \times 4i)\$ \$9 + 12i - 12i - 16i^2\$ 9 + 16 (since \$i^2 = -1\$) 25 |
7 |
Step |
Simplify the fraction: |
\$(-13 + 41i) / 25\$ |
8 |
Step |
Separate into real and imaginary parts: |
\$-13/25 + (41/25)i\$ ⇒ -0.52 + 1.64i |
9 |
Step |
Therefore, the simplified result of dividing (5 + 7i) by (3 - 4i) is -0.52 + 1.64i. |
|
10 |
Choice.A |
This option is incorrect. While the imaginary part matches our result, the real part should be negative, not positive |
1 + 1.64i |
11 |
Choice.B |
This option is correct. It matches our calculated result of \$(5 + 7i)/(3 - 4i)\$ which is -0.52 + 1.64i |
-0.52 + 1.64i |
12 |
Choice.C |
This option is incorrect. The real part should be negative and the imaginary part should be 1.64i, not 1.04i |
1 + 1.04i |
13 |
Choice.D |
This option is incorrect. The real part is positive when it should be negative, and the imaginary part has the wrong sign |
0.52 - 1.64i |
14 |
Answer |
Option |
B |
15 |
Sumup |
Can you summarize what you’ve understood in the above steps? |
Copyright © 2020-2022 saibook.us Contact: info@saibook.us Version: 1.5 Built: 05-August-2024 09:20AM EST