Question

Write out the first 16 positive integer powers of \(i\) \(\left(i, i^{2}, i^{3}, \ldots, i^{16}\right)\), and write each as \(i,-i, 1\), or \(-1 .\) What pattern do you observe?

Short answer

The powers of \(i\) cycle every four terms: \(i, -1, -i, 1\).

Step-by-step solution

Establish the standard

First, write out the first four powers of \(i\): \(\i\), \(\i^2\), \(\i^3\), \(\i^4\) which are \(i\), \(-1\), \(-i\) and \(1\) respectively.

Write out the powers of i up to 16

Use the standard of step 1 and write the powers of \(i\) cyclically. they are: \(i^{1} = i\), \(i^{2} = -1\), \(i^{3} = -i\), \(i^{4} = 1\), \(i^{5} = i\), \(i^{6} = -1\), \(i^{7} = -i\), \(i^{8} = 1\), \(i^{9} = i\), \(i^{10} = -1\), \(i^{11} = -i\), \(i^{12} = 1\), \(i^{13} = i\), \(i^{14} = -1\), \(i^{15} = -i\), \(i^{16} = 1\).

Identify the pattern

Looking at the list of powers from step 2, a pattern emerges. Starting every 4 terms, the sequence: \(i\), \(-1\), \(-i\), \(1\) repeats.

Key concepts

imaginary unit

When we dive into the world of complex numbers, the imaginary unit, denoted by the letter \(i\), takes center stage. The imaginary unit is a mathematical concept that satisfies the equation \(i^2 = -1\). This can be a bit puzzling at first because traditionally, squaring a number results in a positive outcome in the realm of real numbers. However, \(i\) introduces the realm of imaginary numbers, allowing for new dimensions of number manipulation and calculations.
In practical terms:

• \(i\) is not a real number, but a theoretical construct to help solve equations that involve square roots of negative numbers.
• Imaginary numbers using \(i\) can be combined with real numbers to form complex numbers, such as \(3 + 4i\).

Understanding the imaginary unit is a foundational step towards mastering complex numbers and their applications, whether in engineering or advanced mathematics.

powers of i

Exploring the powers of \(i\) opens a fascinating pattern seen in the calculations. As defined, the imaginary unit sheds light on how its powers evolve:

• \(i^1 = i\)
• \(i^2 = -1\)
• \(i^3 = -i\)
• \(i^4 = 1\)

At this point, a cyclic pattern emerges: the powers of \(i\) repeat every four terms. So, the fifth power \(i^5 = i\), the sixth \(i^6 = -1\), and so on. For students, especially those encountering these concepts for the first time, recognizing this cycle:

• Makes computation with powers of \(i\) manageable and predictable.
• Emphasizes the elegance and simplicity amidst initially complex-seeming ideas.
• Offers groundwork to tackle more complex equations involving imaginary units.

This cyclic behavior showcases the rich structure behind what initially seems like an abstract mathematical concept.

mathematical patterns

Mathematical patterns, such as the ones seen in the powers of \(i\), are not just theoretical amusements. They are fundamental to the way mathematics organizes and predicts relationships. Recognizing these patterns helps in many ways.

• **Predictivity**: Once a pattern is known, you can predict the behavior of numbers without fully recalculating them each time. For \(i\), knowing that it cycles every four powers (\(i\), \(-1\), \(-i\), \(1\)) means you can determine \(i^{17}\) with ease, as it mirrors \(i^1\).
• **Problem Solving**: Patterns provide shortcuts in mathematical problem-solving, enhancing efficiency not only in exams but in real-world applications.
• **Mathematical Beauty**: Observing patterns allows one to appreciate the inherent beauty and symmetry in mathematics. This accessibility can lead to a deeper love and understanding of the subject.

Whether for exams or exploring deeper subjects, recognizing mathematical patterns can simplify complexity, highlight beauty, and enable practical application across various fields of study.