(2+6i)(2-6i)

3 min read Jun 16, 2024
(2+6i)(2-6i)

Exploring the Multiplication of Complex Numbers: (2 + 6i)(2 - 6i)

This article delves into the multiplication of complex numbers, specifically focusing on the product of (2 + 6i) and (2 - 6i). We'll explore the process of multiplication and uncover the intriguing results.

Understanding Complex Numbers

Before we dive into the multiplication, let's briefly recap complex numbers. They are numbers of the form a + bi, where:

  • a is the real part, a regular number.
  • b is the imaginary part, multiplied by the imaginary unit i, where i² = -1.

Multiplying Complex Numbers

To multiply complex numbers, we can use the distributive property, similar to multiplying binomials in algebra.

(2 + 6i)(2 - 6i) = 2(2 - 6i) + 6i(2 - 6i)

Expanding the terms:

= 4 - 12i + 12i - 36i²

Remember, i² = -1. Substituting this value:

= 4 - 12i + 12i - 36(-1)

Combining the real and imaginary terms:

= 4 + 36 = 40

The Significance of the Result

The result, 40, is a real number. This outcome reveals a significant property of complex numbers. When multiplying a complex number with its conjugate (the same number with the opposite sign for the imaginary part), the result is always a real number.

In general:

(a + bi)(a - bi) = a² - (bi)² = a² + b²

The conjugate of (2 + 6i) is (2 - 6i), which explains why the multiplication resulted in a real number.

Conclusion

Through this exploration, we've seen how multiplying complex numbers can lead to surprising results. We discovered that multiplying a complex number by its conjugate always yields a real number. This concept has important applications in various fields, including mathematics, physics, and engineering.

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