Math Problem Statement

solve the system of equations x^2 = y and y^2 = x

Solution

Let's solve the system of equations:

  1. x2=yx^2 = y
  2. y2=xy^2 = x

We will solve this system by substitution and by considering different cases for the values of xx and yy.

Step 1: Substitution

From equation (1), we have y=x2y = x^2. Substituting this into equation (2), we get: (x2)2=x(x^2)^2 = x Simplifying, this becomes: x4=xx^4 = x This equation can be rewritten as: x4x=0x^4 - x = 0 Factoring out xx, we get: x(x31)=0x(x^3 - 1) = 0 This further factors into: x(x1)(x2+x+1)=0x(x-1)(x^2 + x + 1) = 0

Step 2: Finding Solutions

This equation gives us three potential solutions for xx:

  1. x=0x = 0
  2. x=1x = 1
  3. x2+x+1=0x^2 + x + 1 = 0

Case 1: x=0x = 0

If x=0x = 0, substituting into equation (1) gives: y=02=0y = 0^2 = 0 So, one solution is (0,0)(0, 0).

Case 2: x=1x = 1

If x=1x = 1, substituting into equation (1) gives: y=12=1y = 1^2 = 1 So, another solution is (1,1)(1, 1).

Case 3: x2+x+1=0x^2 + x + 1 = 0

To solve x2+x+1=0x^2 + x + 1 = 0, we can use the quadratic formula: x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} Here, a=1a = 1, b=1b = 1, and c=1c = 1: x=1±1241121x = \frac{-1 \pm \sqrt{1^2 - 4 \cdot 1 \cdot 1}}{2 \cdot 1} x=1±142x = \frac{-1 \pm \sqrt{1 - 4}}{2} x=1±32x = \frac{-1 \pm \sqrt{-3}}{2} x=1±i32x = \frac{-1 \pm i\sqrt{3}}{2} This gives us two complex solutions for xx: x=1+i32andx=1i32x = \frac{-1 + i\sqrt{3}}{2} \quad \text{and} \quad x = \frac{-1 - i\sqrt{3}}{2} Let's denote these solutions as ω\omega and ω2\omega^2, which are the complex cube roots of unity (where ω=e2πi/3\omega = e^{2\pi i / 3} and ω2=e4πi/3\omega^2 = e^{4\pi i / 3}).

Since y=x2y = x^2, we find the corresponding yy values:

  1. For x=ωx = \omega, y=ω2y = \omega^2.
  2. For x=ω2x = \omega^2, y=ωy = \omega.

Final Solutions

The solutions to the system of equations are:

  1. (0,0)(0, 0)
  2. (1,1)(1, 1)
  3. (1+i32,1i32)\left( \frac{-1 + i\sqrt{3}}{2}, \frac{-1 - i\sqrt{3}}{2} \right)
  4. (1i32,1+i32)\left( \frac{-1 - i\sqrt{3}}{2}, \frac{-1 + i\sqrt{3}}{2} \right)

Do you want more details on any of these solutions or have any questions?

Here are 5 related questions to consider:

  1. How do we solve similar systems involving square roots or higher powers?
  2. What is the geometric interpretation of the real solutions (0,0)(0, 0) and (1,1)(1, 1)?
  3. How can we graphically represent the complex solutions in the complex plane?
  4. What are the properties of the complex cube roots of unity?
  5. How does this problem generalize to higher powers, such as xn=yx^n = y and yn=xy^n = x?

Tip: When solving polynomial equations with complex solutions, consider the symmetries and properties of roots of unity.

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Equations
Complex Numbers
Roots of Unity

Formulas

Quadratic equation formula: x = (-b ± √(b^2 - 4ac)) / 2a
Factoring polynomials: x(x^3 - 1) = 0

Theorems

Quadratic formula
Properties of complex cube roots of unity

Suitable Grade Level

Grades 11-12