Math Problem Statement

Find the value of w given that w = -z/z^2 and z = 1 - 3i.

Solution

From the image, it appears you have an expression involving complex numbers. Here's what I can read from the text:

w=zz2w = -\frac{z}{z^2} with the given condition that z=13iz = 1 - 3i, where ii represents the imaginary unit.

Let me solve this step by step:

  1. Given equation: w=zz2w = -\frac{z}{z^2}

  2. Substitute z=13iz = 1 - 3i: w=13i(13i)2w = -\frac{1 - 3i}{(1 - 3i)^2}

  3. Simplify (13i)2(1 - 3i)^2: (13i)2=122(1)(3i)+(3i)2=16i+9(1)=16i9=86i(1 - 3i)^2 = 1^2 - 2(1)(3i) + (3i)^2 = 1 - 6i + 9(-1) = 1 - 6i - 9 = -8 - 6i

  4. Now substitute this result back into the expression for ww: w=13i86iw = -\frac{1 - 3i}{-8 - 6i}

  5. Simplify the fraction by multiplying both the numerator and denominator by the conjugate of the denominator 8+6i-8 + 6i: w=(13i)(8+6i)(86i)(8+6i)w = -\frac{(1 - 3i)(-8 + 6i)}{(-8 - 6i)(-8 + 6i)}

  6. Simplify the denominator (86i)(8+6i)(-8 - 6i)(-8 + 6i): (86i)(8+6i)=64+36=100(-8 - 6i)(-8 + 6i) = 64 + 36 = 100

  7. Expand the numerator (13i)(8+6i)(1 - 3i)(-8 + 6i): (1)(8)+(1)(6i)+(3i)(8)+(3i)(6i)=8+6i+24i18i2=8+30i+18=10+30i(1)(-8) + (1)(6i) + (-3i)(-8) + (-3i)(6i) = -8 + 6i + 24i - 18i^2 = -8 + 30i + 18 = 10 + 30i

  8. Thus, the expression for ww becomes: w=10+30i100=(10100+30i100)=(0.1+0.3i)w = -\frac{10 + 30i}{100} = -\left( \frac{10}{100} + \frac{30i}{100} \right) = -\left( 0.1 + 0.3i \right)

  9. Final result: w=0.10.3iw = -0.1 - 0.3i

So, w=0.10.3iw = -0.1 - 0.3i.

Do you want further details or clarifications?

Expanding your understanding:

  1. How do you calculate the modulus of a complex number like w=0.10.3iw = -0.1 - 0.3i?
  2. What is the geometric interpretation of multiplying by the conjugate when simplifying complex fractions?
  3. Can you find the argument of ww?
  4. How does multiplying complex numbers affect their magnitudes and angles in the complex plane?
  5. What are other methods to simplify complex fractions?

Tip:

When simplifying complex expressions, always try to multiply by the conjugate to eliminate the imaginary part in the denominator.

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Algebra

Formulas

w = -z/z^2
Multiplication of complex numbers by their conjugates
Simplification of complex fractions

Theorems

Properties of complex conjugates

Suitable Grade Level

Grades 10-12