Simplify [tex]\frac{z_2}{z_1}[/tex] if [tex]z_1=1+i[/tex] and [tex]z_2=2-2\sqrt{3}i[/tex].

A. [tex]1-\sqrt{3}-i(1+\sqrt{3})[/tex]
B. [tex]1-\sqrt{3}+i(1-\sqrt{3})[/tex]
C. [tex]1-\sqrt{3}[/tex]
D. [tex]1+\sqrt{3}[/tex]



Answer :

To simplify [tex]\(\frac{z_2}{z_1}\)[/tex] where [tex]\(z_1 = 1 + i\)[/tex] and [tex]\(z_2 = 2 - 2\sqrt{3}i\)[/tex], follow these steps:

1. Write down the complex numbers:

Let [tex]\(z_1 = 1 + i\)[/tex] and [tex]\(z_2 = 2 - 2\sqrt{3}i\)[/tex].

2. Understand the division of complex numbers:

To divide two complex numbers, we can multiply the numerator and the denominator by the conjugate of the denominator. The conjugate of [tex]\(z_1 = 1 + i\)[/tex] is [tex]\(1 - i\)[/tex].

3. Set up the division:

[tex]\[ \frac{z_2}{z_1} = \frac{2 - 2\sqrt{3}i}{1 + i} \cdot \frac{1 - i}{1 - i} \][/tex]

4. Multiply the numerators and the denominators:

[tex]\[ \text{Numerator: } (2 - 2\sqrt{3}i)(1 - i) \][/tex]

Using the distributive property:

[tex]\[ (2 - 2\sqrt{3}i)(1 - i) = 2 \cdot 1 + 2 \cdot (-i) - 2\sqrt{3}i \cdot 1 - 2\sqrt{3}i \cdot (-i) \][/tex]

Simplify each term:

[tex]\[ = 2 - 2i - 2\sqrt{3}i + 2\sqrt{3}i^2 = 2 - 2i - 2\sqrt{3}i + 2\sqrt{3}(-1) \][/tex]
[tex]\[ = 2 - 2i - 2\sqrt{3}i - 2\sqrt{3} \][/tex]
[tex]\[ = (2 - 2\sqrt{3}) + (-2 - 2\sqrt{3})i \][/tex]

5. Multiply the denominators:

[tex]\[ \text{Denominator: } (1 + i)(1 - i) \][/tex]

Using the distributive property:

[tex]\[ = 1 \cdot 1 + 1 \cdot (-i) + i \cdot 1 + i \cdot (-i) \][/tex]
[tex]\[ = 1 - i + i - i^2 \][/tex]
[tex]\[ = 1 - i^2 = 1 - (-1) = 1 + 1 = 2 \][/tex]

6. Combine the terms:

[tex]\[ \frac{z_2}{z_1} = \frac{(2 - 2\sqrt{3}) + (-2 - 2\sqrt{3})i}{2} \][/tex]

Simplify the division:

[tex]\[ = \frac{2 - 2\sqrt{3}}{2} + \frac{(-2 - 2\sqrt{3})i}{2} \][/tex]
[tex]\[ = 1 - \sqrt{3} - i(1 + \sqrt{3}) \][/tex]

Therefore, the simplified form of [tex]\(\frac{z_2}{z_1}\)[/tex] is:

[tex]\[ 1 - \sqrt{3} - i(1 + \sqrt{3}) \][/tex]

The correct answer is:

A. [tex]\(1 - \sqrt{3} - i(1 + \sqrt{3})\)[/tex]