Chapter 2: Problem 25
If \(z=(i)^{(i)^{(i)}}\) where \(i=\sqrt{-1}\), then \(|z|\) is equal to a. b. \(e^{-\sqrt{2}} \quad\) c. \(e^{-x}\) d. none of these
Short Answer
Expert verified
The modulus \(|z| = e^{-\frac{\pi}{2}}\), an option is not explicitly listed (option b is incorrect).
Step by step solution
01
Simplify the Expression
To simplify \(z = (i)^{(i)^{(i)}}\), we start with the innermost expression and work our way outward. We need to determine \((i)^i\) first.
02
Calculate \((i)^i\) and Its Modulus
We know \(i = e^{i\frac{\pi}{2}}\). Thus, \((i)^i = \left(e^{i\frac{\pi}{2}}\right)^i = e^{-\frac{\pi}{2}}\).To find the modulus of this expression, we calculate \(|e^{-\frac{\pi}{2}}| = e^{-\frac{\pi}{2}}\).
03
Raise to the Power of \(i\) Again
Now we calculate \((i)^{(i)^i} = (i)^{e^{-\frac{\pi}{2}}}\).Using the property \(e^{w} = e^{x+iy} = e^x e^{iy}\), express the exponent. Here, \(x = y = 0\), so the modulus remains \(e^x = e^0 = 1\).
04
Compute the Modulus of Final Expression
Since the expression \((i)^{e^{-\frac{\pi}{2}}}\) is complex with a real part (due to real exponent results), its modulus is the same as \(e^{-\frac{\pi}{2}}\) because raising to the power of \(i\) with a real exponent retains the modulus.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Modulus
The modulus of a complex number is an essential concept in understanding the actions and effects of complex exponents, like in our exercise involving the expression \((i)^{(i)^{(i)}}\). A complex number is typically expressed as \(z = x + yi\), where \(x\) is the real part and \(yi\) is the imaginary part. The modulus of this complex number is a measure of its magnitude or distance from the origin in the complex plane. This is computed as: \[|z| = \sqrt{x^2 + y^2}\].
- The modulus is always a non-negative real number.
- For any given complex number, it helps to visualize its position in the complex plane.
- In some cases, like when dealing with exponents in complex numbers, it aids in simplifying expressions and calculating results.
Complex Exponentiation
Complex exponentiation involves raising a complex number to the power of another complex number. This can seem a bit daunting at first, but it becomes manageable once you understand Euler's formula and logarithms in the context of complex numbers.Let's revisit Euler's wonderful formula, which is key:\[e^{ix} = \cos(x) + i\sin(x)\].
- It allows us to represent the imaginary unit, \(i\), as a complex exponential: \(i = e^{i\frac{\pi}{2}}\).
- Thus, when raising \(i\) to the power of \(i\) itself, \((i)^i = \left(e^{i\frac{\pi}{2}}\right)^i\), which simplifies using properties of exponents to \(e^{-\frac{\pi}{2}}\).
- In this context, exponential operations like these remain very focused on determining real-valued results for modulus or magnitudes where possible.
Imaginary Unit
The imaginary unit, \(i\), is a fundamental building block in the realm of complex numbers. It is defined as the square root of -1, represented as \(i^2 = -1\). This unique property means that complex numbers extend the real number system into a new dimension of numbers that can be visualized as residing on a plane, instead of a line.
- Complex numbers take the form \(x + yi\), where \(x\) and \(y\) are real numbers.
- The imaginary unit \(i\) gives us a way to solve equations that involve taking the square roots of negative numbers.
- For example, \(\sqrt{-1} = i\) and it provides symmetry and balance between dimensions in mathematical models.