Math Problem Statement

Find two complex numbers whose squares equal 5 - 12i.

Solution

The problem in the image asks to find two complex numbers whose squares equal 512i5 - 12i.

Let the complex number be of the form z=a+biz = a + bi, where aa and bb are real numbers. To find zz, we square it and equate it to 512i5 - 12i.

Step-by-step approach:

  1. z2=(a+bi)2=a2+2abi+(bi)2=a2b2+2abiz^2 = (a + bi)^2 = a^2 + 2abi + (bi)^2 = a^2 - b^2 + 2abi.
  2. We know z2=512iz^2 = 5 - 12i, so we equate real and imaginary parts:
    • Real part: a2b2=5a^2 - b^2 = 5
    • Imaginary part: 2ab=122ab = -12

Now, let's solve this system of equations.

System of equations:

  1. a2b2=5a^2 - b^2 = 5 (Real part)
  2. 2ab=122ab = -12 (Imaginary part)

From the second equation, solve for bb in terms of aa: b=122a=6ab = \frac{-12}{2a} = \frac{-6}{a}

Substituting into the first equation:

a2(6a)2=5a^2 - \left( \frac{-6}{a} \right)^2 = 5 a236a2=5a^2 - \frac{36}{a^2} = 5

Now, let's solve this equation for aa. I will calculate this next.The solutions for aa are a=3a = -3, a=3a = 3, a=2ia = -2i, and a=2ia = 2i.

However, since aa is a real number (for z=a+biz = a + bi), we discard the imaginary solutions a=2ia = -2i and a=2ia = 2i.

Thus, a=3a = 3 or a=3a = -3.

Now, solving for bb:

Using b=6ab = \frac{-6}{a}:

  • If a=3a = 3, then b=63=2b = \frac{-6}{3} = -2.
  • If a=3a = -3, then b=63=2b = \frac{-6}{-3} = 2.

The two complex numbers are:

  1. z1=32iz_1 = 3 - 2i
  2. z2=3+2iz_2 = -3 + 2i

These are the two complex numbers whose squares equal 512i5 - 12i.

Would you like more details or have any further questions?

Here are 5 related questions:

  1. How do you verify that squaring 32i3 - 2i gives 512i5 - 12i?
  2. Can you explain why we equate real and imaginary parts separately?
  3. How do we solve complex number equations geometrically?
  4. What is the general form of a complex number and its conjugate?
  5. What happens when you add and multiply two complex numbers?

Tip: Squaring a complex number involves expanding using the distributive property and remembering that i2=1i^2 = -1.

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Equating Real and Imaginary Parts
Solving Systems of Equations

Formulas

(a + bi)^2 = a^2 - b^2 + 2abi
System of equations: a^2 - b^2 = real part, 2ab = imaginary part

Theorems

Basic Complex Number Multiplication
Equating Real and Imaginary Parts

Suitable Grade Level

Grades 11-12 or College