Math Problem Statement

Solve z

z^2+ 2z̅+ 2 = 0 for z, where z ∈ C.

Solution

To solve z2+2z+2=0z^2 + 2\overline{z} + 2 = 0 where zCz \in \mathbb{C}, we proceed with the following steps:

  1. Express zz and z\overline{z}: Let z=x+yiz = x + yi where x,yRx, y \in \mathbb{R}. Then, z=xyi\overline{z} = x - yi.

  2. Substitute zz and z\overline{z} into the equation: (x+yi)2+2(xyi)+2=0(x + yi)^2 + 2(x - yi) + 2 = 0

  3. Expand and simplify: (x+yi)2=x2+2xyiy2(x + yi)^2 = x^2 + 2xyi - y^2 So the equation becomes: x2+2xyiy2+2x2yi+2=0x^2 + 2xyi - y^2 + 2x - 2yi + 2 = 0

  4. Separate the real and imaginary parts: (x2y2+2x+2)+(2xy2y)i=0(x^2 - y^2 + 2x + 2) + (2xy - 2y)i = 0

    This gives us two equations: x2y2+2x+2=0(real part)x^2 - y^2 + 2x + 2 = 0 \quad \text{(real part)} 2xy2y=0(imaginary part)2xy - 2y = 0 \quad \text{(imaginary part)}

  5. Solve the imaginary part equation first: 2y(x1)=02y(x - 1) = 0

    This implies: y=0orx=1y = 0 \quad \text{or} \quad x = 1

  6. Consider each case:

    • Case 1: y=0y = 0 x2+2x+2=0x^2 + 2x + 2 = 0 Solve the quadratic equation: x=2±482=2±42=2±2i2=1±ix = \frac{-2 \pm \sqrt{4 - 8}}{2} = \frac{-2 \pm \sqrt{-4}}{2} = \frac{-2 \pm 2i}{2} = -1 \pm i So, z=1+iz = -1 + i and z=1iz = -1 - i.

    • Case 2: x=1x = 1 1y2+2+2=01 - y^2 + 2 + 2 = 0 3y2=03 - y^2 = 0 y2=3y^2 = 3 y=±3y = \pm \sqrt{3} So, z=1+3iz = 1 + \sqrt{3}i and z=13iz = 1 - \sqrt{3}i.

  7. Combine the solutions: z=1+i,z=1i,z=1+3i,z=13iz = -1 + i, \quad z = -1 - i, \quad z = 1 + \sqrt{3}i, \quad z = 1 - \sqrt{3}i

Thus, the solutions to z2+2z+2=0z^2 + 2\overline{z} + 2 = 0 are: z=1+i,z=1i,z=1+3i,z=13iz = -1 + i, \quad z = -1 - i, \quad z = 1 + \sqrt{3}i, \quad z = 1 - \sqrt{3}i

Would you like more details or have any questions?

Here are 5 additional questions you might be interested in:

  1. How do you solve higher-degree polynomial equations in complex numbers?
  2. What is the significance of the roots of complex equations in the complex plane?
  3. Can you explain the concept of the complex conjugate root theorem?
  4. How do you determine the nature of the roots of a complex quadratic equation?
  5. What are some applications of complex numbers in engineering and physics?

Tip: When solving complex equations, always consider both the real and imaginary parts separately. This often simplifies the problem into manageable real-number equations.

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Quadratic Equations

Formulas

Quadratic equation

Theorems

Complex conjugate root theorem

Suitable Grade Level

Grades 11-12