Chapter 2: Problem 82
In Exercises 79 - 88, simplify the complex number and write it in standard form. \( (-i)^3 \)
Short Answer
Expert verified
The simplified standard form of the complex number \( (-i)^3 \) is \( i \).
Step by step solution
01
Recognize the Power of i
We know that the powers of i follow a consistent cycle: \( i^1 = i \), \( i^2 = -1 \), \( i^3 = -i \), and \( i^4 = 1 \). This pattern then repeats for every fourth power of i. In this case, we have \( (-i)^3 \), which we need to simplify.
02
Apply Power Rules
A rule of exponential functions is that a product raised to an exponent is equal to each factor raised to that same exponent. Therefore, \( (-i)^3 \) can be rewritten as \( -1^3 * i^3 \).
03
Simplify the Expression
We can now simplify this using the power cycle values of i and knowing that -1 raised to any odd power equals -1: \( -1^3 * i^3 = -1 * -i = i\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Standard Form of Complex Numbers
Complex numbers are a blend of real and imaginary numbers and are pivotal in various fields of mathematics and engineering. The standard form of a complex number is expressed as \( a + bi \), where \( a \) is the real part, and \( bi \) is the imaginary part. In this notation, \( i \) represents the imaginary unit, the square root of \(-1\), and both \( a \) and \( b \) are real numbers. The beauty of this form is its straightforwardness—it tells us exactly how much real and imaginary substance a complex number contains.
To successfully write a complex number in standard form, you must have a clear understanding of the basic arithmetic involving real and imaginary parts separately.
To successfully write a complex number in standard form, you must have a clear understanding of the basic arithmetic involving real and imaginary parts separately.
- If given in another format, convert it by simplifying the imaginary parts using the properties of \( i \).
- Combine like terms, much like you would in algebra.
- Make sure the final expression has no other radicals or powers of \( i \); it should look just \( a + bi \).
Powers of i
In the realm of complex numbers, the symbol \( i \) is quite the celebrity, representing the core concept of an imaginary unit, which is famously defined as the square root of \(-1\). When it comes to the powers of \( i \), they follow a cyclic pattern that repeats every four powers. This can be a super helpful shortcut when simplifying expressions involving \( i \).
The cycle looks like this:
The cycle looks like this:
- \( i^1 = i \)
- \( i^2 = -1 \)
- \( i^3 = -i \)
- \( i^4 = 1 \)
Exponential Functions
Diving into the fascinating world of exponential functions, we come across expressions where numbers or variables are raised to powers. In mathematics, an exponential function is a powerhouse—it represents growth or decay processes, and it comes in particularly handy in complex numbers when working with powers of \( i \).
An exponential function typically looks like \( f(x) = a^x \), where \( a \) is a constant and \( x \) can be any real number. One of the golden rules is that when you raise a product to a power, you can apply the power to each factor individually. For example, \( (ab)^n = a^n b^n \). This rule is essential when you're working with expressions like \( (-i)^3 \); you break it down to \( (-1)^3 \) and \( i^3 \) independently.
An exponential function typically looks like \( f(x) = a^x \), where \( a \) is a constant and \( x \) can be any real number. One of the golden rules is that when you raise a product to a power, you can apply the power to each factor individually. For example, \( (ab)^n = a^n b^n \). This rule is essential when you're working with expressions like \( (-i)^3 \); you break it down to \( (-1)^3 \) and \( i^3 \) independently.
- This helps you manage the simplification of complex numbers with a lot more ease.
- It also allows you to separate the real and imaginary components when multiplying or raising to powers.