(3+5i)^2

2 min read Jun 16, 2024
(3+5i)^2

Squaring Complex Numbers: A Look at (3+5i)^2

In the world of complex numbers, squaring a number like (3+5i) might seem daunting, but it's actually quite straightforward. Let's break down the process step-by-step:

Understanding Complex Numbers

A complex number is a number of the form a + bi, where a and b are real numbers, and i is the imaginary unit, defined as the square root of -1.

Expanding the Square

To square (3+5i), we simply multiply it by itself:

(3 + 5i)² = (3 + 5i)(3 + 5i)

Now, we can use the distributive property (or FOIL method) to expand this expression:

(3 + 5i)(3 + 5i) = 3(3) + 3(5i) + 5i(3) + 5i(5i)

Simplifying the Expression

Let's simplify each term:

  • 3(3) = 9
  • 3(5i) = 15i
  • 5i(3) = 15i
  • 5i(5i) = 25i²

Remember that i² = -1. Substituting this into our expression:

9 + 15i + 15i + 25(-1)

Combining Like Terms

Now, combine the real and imaginary terms:

(9 - 25) + (15 + 15)i

This simplifies to:

-16 + 30i

Conclusion

Therefore, (3 + 5i)² is equal to -16 + 30i. By understanding the properties of complex numbers and using the distributive property, we can easily square complex numbers and obtain a new complex number as a result.

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