Math Problem Statement

let z=1/3 + ((square root of 3) /2)i. solve for (z̄)^4. Note z̄ is the conjugate of z

Solution

We are given:

z=13+32iz = \frac{1}{3} + \frac{\sqrt{3}}{2} i

and need to solve for z4\overline{z}^4, where z\overline{z} is the complex conjugate of zz.

Step 1: Find the complex conjugate of zz

The complex conjugate of z=13+32iz = \frac{1}{3} + \frac{\sqrt{3}}{2} i is obtained by changing the sign of the imaginary part. Therefore:

z=1332i\overline{z} = \frac{1}{3} - \frac{\sqrt{3}}{2} i

Step 2: Express z\overline{z} in polar form

To simplify the calculation of z4\overline{z}^4, it's helpful to convert z\overline{z} to polar form. The polar form of a complex number is given by:

z=r(cosθ+isinθ)\overline{z} = r \left( \cos \theta + i \sin \theta \right)

where:

  • rr is the modulus of z\overline{z},
  • θ\theta is the argument (angle) of z\overline{z}.

Modulus rr:

The modulus rr of z\overline{z} is:

r=z=(13)2+(32)2r = \left| \overline{z} \right| = \sqrt{\left( \frac{1}{3} \right)^2 + \left( \frac{-\sqrt{3}}{2} \right)^2}

r = \sqrt{\frac{1}{9} + \frac{3}{4}} = \sqrt{\frac{1 + 6.75}{9}} = \sqrt{\frac{7.75}{9}} = \frac{\sqrt{31}{6}}

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Conjugates
Polar Form

Formulas

Complex Conjugate: z̄ = a - bi for z = a + bi
Modulus: r = √(a^2 + b^2)
Polar Form: z = r(cos(θ) + i sin(θ))

Theorems

De Moivre's Theorem

Suitable Grade Level

Grades 11-12 (Advanced High School)