(5+3i)(5-3i) In Standard Form

3 min read Jun 16, 2024
(5+3i)(5-3i) In Standard Form

Simplifying Complex Numbers: (5 + 3i)(5 - 3i)

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

This article will walk through simplifying the expression (5 + 3i)(5 - 3i) into standard form.

Understanding Complex Numbers

  • Real Part: The real part of a complex number is the term without the imaginary unit i. In the expression (5 + 3i), the real part is 5.
  • Imaginary Part: The imaginary part of a complex number is the term multiplied by the imaginary unit i. In the expression (5 + 3i), the imaginary part is 3.

Simplifying the Expression

We can simplify the expression (5 + 3i)(5 - 3i) by applying the distributive property (also known as FOIL).

1. Distribute the terms: (5 + 3i)(5 - 3i) = (5 * 5) + (5 * -3i) + (3i * 5) + (3i * -3i)

2. Simplify the multiplication: = 25 - 15i + 15i - 9i²

3. Remember that i² = -1: = 25 - 15i + 15i - 9(-1)

4. Combine like terms: = 25 + 9

5. Final Answer: = 34

Conclusion

By applying the distributive property and substituting i² with -1, we have successfully simplified the expression (5 + 3i)(5 - 3i) to its standard form, 34. This result demonstrates an important property of complex numbers: multiplying a complex number by its conjugate (the complex number with the opposite sign for the imaginary part) results in a real number. In this case, the conjugate of (5 + 3i) is (5 - 3i).

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