Chapter 10: Problem 95
In Exercises \(85-100,\) simplify each expression. $$(-i)^{4}$$
Short Answer
Expert verified
The simplification of \( (-i)^{4} \) is 1.
Step by step solution
01
Substitute the Value of \(i^2\)
The first part is to understand the nature of the imaginary unit \(i\). Remember that \(i^2 = -1\). Knowing this, we can raise \(i\) to the power of 4 by multiplying two instances of \(i^2\) together. It becomes \( (-i)^4 = ((-i)^2)^2 = ((-1)^2 * i^2)^2 \).
02
Simplify the Expression
The second part is to simplify the expression. \( ((-1)^2 * i^2)^2 = (1* -1 )^2 =-1^2 = 1 \).
03
Final Result
So, the simplification of the given expression \( {-i}^4 \) is 1.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Imaginary Unit
Complex numbers are a fascinating realm of mathematics, and at the heart of complex numbers lies the imaginary unit, denoted by the symbol \( i \). Essentially, \( i \) is defined such that \( i^2 = -1 \). This concept may initially seem puzzling because we aren't used to taking the square root of negative numbers.
Here's where the imaginary unit comes into play:
Here's where the imaginary unit comes into play:
- The imaginary unit \( i \) allows us to work with numbers that include roots of negative numbers, transforming these roots into manageable elements in mathematical expressions.
- When you encounter \( i \) in an expression, it signifies the inclusion of an imaginary component, widening the scope of possible solutions in equations.
Exponents
Understanding exponents is vital in simplifying expressions, especially when involving complex numbers like \( (-i)^4 \). Exponents denote multiplying a number by itself a certain number of times. For example, \( a^n \) means multiplying \( a \) by itself \( n \) times.
In complex numbers and expressions:
In complex numbers and expressions:
- Raising \( i \) to various powers reveals a cycle, due to its definition \( i^2 = -1 \).
- Consider \( i^1 = i \), \( i^2 = -1 \), \( i^3 = -i \), and \( i^4 = 1 \). Notice how every fourth power of \( i \) loops back to 1.
- We recognize that \( (-i)^2 = (-1)^2 \times i^2 = 1 \times (-1) = -1 \).
- Therefore, \( (-i)^4 = ((-i)^2)^2 = (-1)^2 = 1 \).
Simplification of Expressions
Simplifying expressions, especially those with complex numbers, requires applying rules judiciously to reduce a complex appearing concept into a more understandable form. The simplification process is systematic:
- Identify known rules and properties: Like how you recognize \( i^2 = -1 \) as a fundamental property of \( i \).
- Apply logical steps: Use algebraic manipulations to break down expressions into simpler components, ensuring each step logically follows the previous one.
- Keep track of signs: Complex numbers involve careful attention to negative and positive signs as these influence the final outcome significantly.
- Start by recognizing \( (-i)^2 = (-1)^2 \times i^2 = -1 \), which simplifies to use in subsequent steps.
- Raise the result to the power required, here \( ((-i)^2)^2 = (-1)^2 = 1 \).