(6 + 3i)(6 − 3i) = (4 − 5i)(4 + 5i) = (−3 + 8i)(−3 − 8i) =

3 min read Jun 16, 2024

The Beauty of Complex Conjugates: A Journey Through (6 + 3i)(6 − 3i) = (4 − 5i)(4 + 5i) = (−3 + 8i)(−3 − 8i)

This intriguing equation presents a fascinating exploration of complex conjugates and their unique properties. Let's delve into the beauty behind this mathematical puzzle.

Understanding Complex Conjugates

A complex conjugate is formed by simply changing the sign of the imaginary part of a complex number. For example, the conjugate of (a + bi) is (a - bi).

The Magic of Multiplication

When you multiply a complex number by its conjugate, something remarkable happens: the imaginary terms disappear!

Let's see how this works with our examples:

Example 1: (6 + 3i)(6 − 3i)

Expanding the product, we get: 36 - 18i + 18i - 9i²
Since i² = -1, the equation simplifies to: 36 + 9 = 45

Example 2: (4 − 5i)(4 + 5i)

Expanding: 16 + 20i - 20i - 25i²
Simplifying: 16 + 25 = 41

Example 3: (−3 + 8i)(−3 − 8i)

Expanding: 9 + 24i - 24i - 64i²
Simplifying: 9 + 64 = 73

The Power of Conjugates

The result of multiplying a complex number by its conjugate is always a real number. This property is incredibly useful in various mathematical applications, including:

Dividing complex numbers: Multiplying both the numerator and denominator of a complex fraction by the conjugate of the denominator allows you to simplify the expression and express the result in the form (a + bi).
Solving equations: Complex conjugates are essential for finding the roots of polynomial equations.
Engineering applications: They find applications in electrical engineering, signal processing, and many other fields.

Conclusion

The equation (6 + 3i)(6 − 3i) = (4 − 5i)(4 + 5i) = (−3 + 8i)(−3 − 8i) highlights the elegance and power of complex conjugates. By understanding their properties, we unlock a world of mathematical possibilities and gain valuable insights into the behavior of complex numbers.