Find The Distance Between 2-4i And 6+i

Finding the Distance Between Two Complex Numbers: A Comprehensive Guide

This article will guide you through the process of calculating the distance between two complex numbers, specifically 2 - 4i and 6 + i. We'll explore the underlying mathematical concepts, provide a step-by-step solution, and delve into the geometric interpretation of complex numbers to solidify your understanding. By the end, you'll not only know how to solve this specific problem but also be equipped to calculate the distance between any two complex numbers. This method is crucial in various fields, including electrical engineering, signal processing, and quantum mechanics.

Introduction to Complex Numbers and the Complex Plane

Before diving into the distance calculation, let's refresh our understanding of complex numbers. A complex number is a number that can be 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 (√-1). a is called the real part, and b is called the imaginary part of the complex number.

We can represent complex numbers geometrically on a complex plane (also known as an Argand diagram). The horizontal axis represents the real part, and the vertical axis represents the imaginary part. Each complex number corresponds to a unique point on this plane. For example, the complex number 2 - 4i would be plotted at the point (2, -4).

Visualizing the Distance: The Modulus and the Distance Formula

The distance between two complex numbers on the complex plane is equivalent to finding the distance between two points in a Cartesian coordinate system. This distance is often referred to as the magnitude or modulus of the difference between the two complex numbers.

Let's consider two complex numbers, z₁ = x₁ + y₁i and z₂ = x₂ + y₂i. The distance d between these two points is given by the distance formula derived from the Pythagorean theorem:

d = √[(x₂ - x₁)² + (y₂ - y₁)²]

This formula directly calculates the length of the hypotenuse of a right-angled triangle formed by the difference in the real parts and the difference in the imaginary parts.

Step-by-Step Calculation: Finding the Distance Between 2 - 4i and 6 + i

Now, let's apply this formula to find the distance between the complex numbers 2 - 4i and 6 + i.

1. Identify the Real and Imaginary Parts:

• For z₁ = 2 - 4i, we have x₁ = 2 and y₁ = -4.
• For z₂ = 6 + i, we have x₂ = 6 and y₂ = 1.

2. Calculate the Differences:

• Difference in real parts: x₂ - x₁ = 6 - 2 = 4
• Difference in imaginary parts: y₂ - y₁ = 1 - (-4) = 5

3. Apply the Distance Formula:

Substitute the differences into the distance formula:

d = √[(4)² + (5)²] = √[16 + 25] = √41*

Therefore, the distance between the complex numbers 2 - 4i and 6 + i is √41. This is an irrational number, approximately equal to 6.403.

Geometric Interpretation and Vector Representation

The distance calculation can also be understood using vector representation. We can consider each complex number as a vector originating from the origin (0, 0) to the point representing the complex number on the complex plane. The difference between two complex numbers can then be interpreted as the vector connecting the two points. The magnitude of this difference vector is simply the distance between the two points.

Understanding the Modulus of a Complex Number

The modulus of a complex number z = a + bi, denoted as |z|, is the distance from the origin (0, 0) to the point (a, b) on the complex plane. It's calculated as:

|z| = √(a² + b²)

While we used the distance formula directly between two points, understanding the modulus is fundamental. The distance between two complex numbers z₁ and z₂ can also be calculated as the modulus of their difference: |z₂ - z₁|.

Let’s verify this with our example:

z₂ - z₁ = (6 + i) - (2 - 4i) = 4 + 5i

|z₂ - z₁| = √(4² + 5²) = √41

This confirms our previous result.

Applications of Distance Between Complex Numbers

The concept of distance between complex numbers finds applications in various fields:

• Signal Processing: In representing and manipulating signals, the distance between complex numbers in the frequency domain can help in signal analysis and filtering. For example, determining the proximity of frequencies in a signal.

• Electrical Engineering: Complex numbers are crucial for analyzing alternating current (AC) circuits. The distance between complex impedances helps determine the relationships between different components in a circuit.

• Quantum Mechanics: In quantum mechanics, complex numbers are essential for describing quantum states and wave functions. Distances between quantum states can be relevant to understanding transitions between states.

• Computer Graphics: Complex numbers and their geometric interpretations are used extensively in computer graphics for rotations, transformations, and fractal generation.

• Mathematics: The concept forms the basis for advanced mathematical concepts in complex analysis.

Frequently Asked Questions (FAQ)

Q1: Can the distance between two complex numbers ever be zero?

A1: Yes, the distance is zero only if the two complex numbers are identical (i.e., they represent the same point on the complex plane).

Q2: What if I have complex numbers with large real and imaginary parts? Will the calculation become complicated?

A2: While the numbers might be larger, the process remains the same. Simply apply the distance formula accurately. Calculators or software can assist with the arithmetic.

Q3: Is there a different formula if the complex numbers are represented in polar form?

A3: While complex numbers can be represented in polar form (r(cos θ + i sin θ) or r*e^(iθ)), the distance calculation conceptually remains the same. You would need to convert the polar representation to Cartesian form (a + bi) before applying the distance formula or use a different approach based on the properties of polar coordinates.

Q4: How can I visualize this on a graph?

A4: Plot the points representing the complex numbers (2, -4) and (6, 1) on a Cartesian coordinate system. Draw a line segment connecting these two points. The length of this line segment represents the distance between the two complex numbers, which we calculated as √41.

Conclusion

Calculating the distance between two complex numbers is a straightforward application of the distance formula, rooted in the Pythagorean theorem and readily visualized on the complex plane. This fundamental concept has broad implications across various scientific and engineering disciplines. By understanding the underlying principles and practicing the step-by-step procedure, you can confidently tackle such calculations and appreciate their significance in diverse fields. Remember, the key is to correctly identify the real and imaginary parts and then diligently apply the distance formula. The result, whether a rational or irrational number, represents the true distance between the two points in the complex plane.