Question

Write the conjugate of each complex number. $$5-8 i$$

Short answer

The conjugate of \(5 - 8i\) is \(5 + 8i\).

Step-by-step solution

Understanding Complex Conjugates

The conjugate of a complex number is found by changing the sign of the imaginary part. The complex conjugate of a number in the form of a + bi is a - bi.

Determining the Conjugate

For the complex number \(5 - 8i\), the conjugate is simply \(5 + 8i\). We change the sign of the imaginary part from negative to positive.

Key concepts

Complex Numbers

At the heart of many mathematical operations lies the concept of complex numbers. A complex number consists of two components: a real part and an imaginary part. It is typically expressed in the form of \( a + bi \), where \( a \) represents the real part and \( bi \) represents the imaginary part with \( i \) being the imaginary unit, satisfying the equation \( i^2 = -1 \).

Imagining a complex number might be easier if we picture it on a plane known as the complex plane or Argand plane, where the x-axis represents real numbers and the y-axis represents imaginary numbers. Complex numbers are essential in various fields such as engineering, physics, and computer science because they provide a comprehensive way to describe oscillations, waves, and many other phenomena.

Imaginary Numbers

Imaginary numbers are a fascinating and necessary concept in algebra. They are built upon the imaginary unit \( i \), which is defined as \( i^2 = -1 \). This may seem abstract at first, but imaginary numbers allow us to solve equations that don't have real number solutions.

For example, the square root of a negative number is not definable in the set of real numbers. This is where imaginary numbers come in, giving us the tools to delve deeper into mathematical problems. They are used extensively in complex arithmetic and extend the real number system \( \mathbb{R} \) to the complex number system \( \mathbb{C} \) — a system where any polynomial equation has a root.

Algebra

Algebra is a branch of mathematics dealing with symbols and the rules for manipulating those symbols. It is a unifying thread of almost all of mathematics and includes everything from solving simple equations to studying abstractions such as groups, rings, and fields.

When it comes to complex numbers in algebra, understanding how to perform operations like addition, subtraction, multiplication, and finding complex conjugates is crucial. The concept of complex conjugates, for instance, is used to simplify the division of complex numbers. In algebraic operations, the conjugate \( a - bi \) of a complex number \( a + bi \) is used because it has the special property that multiplying a complex number by its conjugate gives a real number: \( (a + bi)(a - bi) = a^2 + b^2 \). This often helps in resolving equations or simplifying expressions, making this algebraic concept incredibly powerful and essential for understanding more advanced aspects of mathematics.