Chapter 10: Problem 89
Find each power of i. $$ i^{38} $$
Short Answer
Expert verified
i^{38} = -1
Step by step solution
01
Understanding the Cycle of Powers
The powers of the imaginary unit, i, repeat in a cycle: i^1 = i i^2 = -1 i^3 = -i i^4 = 1This cycle repeats every four exponents. Hence, any power of i can be reduced by recognizing its position in this cycle.
02
Divide the Exponent by 4
Determine how many complete cycles fit into the exponent and what remains. Compute this by dividing the exponent, 38, by 4 and finding the remainder: 38 ÷ 4 = 9 remainder 2.
03
Identify the Equivalent Lower Exponent
Using the remainder, identify the corresponding power of i in the cycle: i^{38} is equivalent to i^2.
04
Use the Cycle to Find the Value
From the cycle, i^2 = -1. Hence, i^{38} = -1.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Imaginary Unit
The imaginary unit is a fundamental concept in complex numbers and is denoted by the symbol \(i\). The primary property of \(i\) is that \(i^2 = -1\). This means that \(i\) is the square root of -1. Imaginary numbers are essential because they allow the extension of the real number system to solve equations that do not have real solutions, such as \(x^2 + 1 = 0\). Learning about \(i\) helps in understanding complex numbers and their operations, enabling a range of applications in fields like engineering, physics, and applied mathematics.
Exponent Cycles
One fascinating aspect of the imaginary unit is its exponent cycle. The powers of \(i\) repeat in a predictable pattern every four exponents. Here is how the cycle looks:
- \(i^1 = i\)
- \(i^2 = -1\)
- \(i^3 = -i\)
- \(i^4 = 1\)
- \(i^5 = i\)
- \(i^6 = -1\)
- \(i^7 = -i\)
- \(i^8 = 1\)
Remainder Division
To simplify the powers of \(i\), we use remainder division to determine the position of the exponent in the cycle of four.
For example, to find \(i^{38}\), you divide 38 by 4 and find the remainder:
\(38 \div 4 = 9 \text{ remainder } 2 \).
The remainder, 2, indicates the equivalent lower exponent. This tells us that \(i^{38}\) is the same as \(i^2\), which is -1.
This process helps simplify high exponentiation into manageable pieces using the cycle.
For example, to find \(i^{38}\), you divide 38 by 4 and find the remainder:
\(38 \div 4 = 9 \text{ remainder } 2 \).
The remainder, 2, indicates the equivalent lower exponent. This tells us that \(i^{38}\) is the same as \(i^2\), which is -1.
This process helps simplify high exponentiation into manageable pieces using the cycle.
Complex Numbers
Complex numbers extend the idea of the one-dimensional number line to a two-dimensional plane using the imaginary unit \(i\). A complex number is expressed as \(a + bi\), where \(a\) and \(b\) are real numbers.
In this expression:
Knowledge of complex numbers is crucial in many advanced fields of study, including quantum mechanics, signal processing, and control theory.
In this expression:
- \(a\) is the real part
- \(bi\) is the imaginary part
Knowledge of complex numbers is crucial in many advanced fields of study, including quantum mechanics, signal processing, and control theory.