Chapter 10: Problem 79
Find each power of \(i\) $$ i^{-6} $$
Short Answer
Expert verified
The value of \(i^{-6}\) is \(-1\).
Step by step solution
01
Recall the Powers of i
The numbers based on powers of the imaginary unit \(i\) repeat in cycles of four: \(i^1 = i\), \(i^2 = -1\), \(i^3 = -i\), \(i^4 = 1\). This cycle repeats: \(i^5 = i\), \(i^6 = -1\), etc.
02
Simplify the Negative Exponent
The given expression is \(i^{-6}\). First, use the property of exponents \(a^{-b} = \frac{1}{a^b}\) to rewrite the expression as \(\frac{1}{i^6}\).
03
Determine \(i^6\) Using the Cycle
From the cycle in Step 1, we know that \(i^6 = -1\) because the cycle shows that \(i^2 = -1\) and \(6 \mod 4 = 2\). Hence, \(i^6\) falls at \(i^2\).
04
Simplify the Expression
Substitute the value found in Step 3 into the expression from Step 2: \(\frac{1}{i^6} = \frac{1}{-1} = -1\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Imaginary Numbers
Imaginary numbers might sound like they're made-up, but they are a crucial part of algebra that help solve equations involving square roots of negative numbers. The imaginary unit is denoted by the letter \(i\), and is defined such that \(i^2 = -1\). This definition provides a tool for dealing with square roots of negative numbers, which were once thought impossible.
Here's how it breaks down:
Here's how it breaks down:
- The basic form: Any imaginary number can be expressed as a multiple of \(i\). For example, \(3i, -5i\).
- Complex numbers: When combined with a real number, it forms a complex number, such as \(3 + 4i\).
- Applications: Imaginary numbers, and by extension complex numbers, are useful in various fields such as engineering, quantum physics, and applied mathematics.
Exponent Rules
The rules of exponents are a set of fundamental laws that help simplify expressions involving powers. These rules stay consistent, whether you are dealing with whole numbers, fractions, or even imaginary numbers.
The key rules include:
The key rules include:
- Product of Powers: \(a^m \cdot a^n = a^{m+n}\)
- Power of a Power: \((a^m)^n = a^{m \cdot n}\)
- Power of a Product: \((ab)^n = a^n \cdot b^n\)
- Negative Exponent: \(a^{-n} = \frac{1}{a^n}\)
- Zero Exponent: \(a^0 = 1\), provided \(a eq 0\)
Cyclic Patterns
Cyclic patterns offer an efficient way to manage powers of imaginary numbers. Since the powers of \(i\) repeat in a cycle of four, it simplifies otherwise cumbersome calculations.
Here’s how this cyclicity works:
Here’s how this cyclicity works:
- Powers of \(i\): Begin with \(i^1 = i\) and follow the cycle: \(i^2 = -1\), \(i^3 = -i\), \(i^4 = 1\).
- Repeating Cycle: The cycle repeats every four exponentiations. Thus, \(i^5 = i\) and so on. To find the power, determine the remainder when dividing the exponent by four.
- Use of Modulus: To find any power of \(i\), simply calculate the exponent modulo 4. This gives the equivalent position in the cycle. For example, \(i^6\) is equivalent to \(i^2\) because \(6 \mod 4 = 2\).