Math Problem Statement

Find the modulus of the complex number z = -4 - 4√3i.

Solution

To solve the problem, we need to determine the modulus of the complex number z=443iz = -4 - 4\sqrt{3}i.


Modulus of a Complex Number

The modulus z|z| of a complex number z=a+biz = a + bi is given by: z=a2+b2|z| = \sqrt{a^2 + b^2} where aa is the real part and bb is the imaginary part.

In this case:

  • a=4a = -4 (real part),
  • b=43b = -4\sqrt{3} (imaginary part).

Calculation of the Modulus

  1. Square the real part aa: a2=(4)2=16a^2 = (-4)^2 = 16

  2. Square the imaginary part bb: b2=(43)2=163=48b^2 = (-4\sqrt{3})^2 = 16 \cdot 3 = 48

  3. Add the squares: a2+b2=16+48=64a^2 + b^2 = 16 + 48 = 64

  4. Take the square root to find the modulus: z=64=8|z| = \sqrt{64} = 8


Answer

The modulus of the complex number z=443iz = -4 - 4\sqrt{3}i is: 8\boxed{8}


Verification of the Options

From the given options:

  • 16316\sqrt{3} → Not correct.
  • 28\sqrt{28} → Simplifies to 272\sqrt{7} ≠ 8.
  • 32\sqrt{32} → Simplifies to 424\sqrt{2} ≠ 8.
  • 88 → Correct.

Do you want me to explain further or clarify any steps?

Related Questions

  1. How do you find the modulus of a complex number geometrically?
  2. What is the conjugate of a complex number z=443iz = -4 - 4\sqrt{3}i?
  3. How do you plot complex numbers on the Argand plane?
  4. How can you generalize the modulus formula for complex numbers?
  5. What is the difference between a real and imaginary part of a complex number?

Tip:

Always square carefully when working with square roots in complex numbers to avoid small calculation errors.

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Modulus of a Complex Number

Formulas

|z| = √(a² + b²), where z = a + bi

Theorems

Pythagorean Theorem for calculating modulus

Suitable Grade Level

Grades 9-11