Chapter 17: Problem 13
In Problems 7-14, express the given function in the form \(f(z)=u+i v .\) $$ f(z)=z+1 / z $$
Short Answer
Expert verified
The function is expressed as \(f(z) = \left(x + \frac{x}{x^2 + y^2}\right) + i\left(y - \frac{y}{x^2 + y^2}\right)\).
Step by step solution
01
Represent Complex Number
Express the complex variable \( z \) in terms of its real and imaginary parts. Let \( z = x + yi \), where \( x \) and \( y \) are real numbers. Here, \( x \) represents the real part, and \( y \) represents the imaginary part.
02
Find the Reciprocal of z
Calculate the reciprocal of \( z \). We have:\[\frac{1}{z} = \frac{1}{x + yi} = \frac{x - yi}{x^2 + y^2}\]Simplify it to:\[\frac{1}{z} = \frac{x}{x^2 + y^2} - i \frac{y}{x^2 + y^2}\]
03
Substitute and Expand f(z)
Substitute \( z = x + yi \) and \( \frac{1}{z} = \frac{x}{x^2 + y^2} - i \frac{y}{x^2 + y^2} \) into the function:\[f(z) = (x + yi) + \left( \frac{x}{x^2 + y^2} - i\frac{y}{x^2 + y^2} \right)\]Combine the real and imaginary parts:
04
Combine Real and Imaginary Parts
Combine the terms to separate the real and imaginary components:Real part:\[u = x + \frac{x}{x^2 + y^2}\]Imaginary part:\[v = y - \frac{y}{x^2 + y^2}\]Thus, \(f(z) = \left(x + \frac{x}{x^2 + y^2}\right) + i\left(y - \frac{y}{x^2 + y^2}\right)\).
05
Express f(z) as u + iv
Express the given function \( f(z) = u + iv \), where:\[u(x, y) = x + \frac{x}{x^2 + y^2}\]\[v(x, y) = y - \frac{y}{x^2 + y^2}\]This represents the function in the desired form.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Complex Functions
Complex functions are like a magical combination of algebra and geometry. They treat numbers as two-dimensional, using both real and imaginary parts. A complex function takes a complex number as input and gives another complex number as output.
Think of it as a machine that processes complex numbers in intriguing ways. In our given exercise, the function is defined as \( f(z) = z + \frac{1}{z} \).
This means we're dealing with a sum involving both the number \( z \) and its reciprocal. Complex functions are widely used in engineering and physics, especially where oscillations and waves are involved. The real and imaginary parts of these functions can tell us a lot about the phenomena we're studying.
Think of it as a machine that processes complex numbers in intriguing ways. In our given exercise, the function is defined as \( f(z) = z + \frac{1}{z} \).
This means we're dealing with a sum involving both the number \( z \) and its reciprocal. Complex functions are widely used in engineering and physics, especially where oscillations and waves are involved. The real and imaginary parts of these functions can tell us a lot about the phenomena we're studying.
Real and Imaginary Parts
In complex numbers, every number has a real part and an imaginary part. These two parts work together to describe the number fully. When you express a complex number in the form \( z = x + yi \):
This results in the real part \( u = x + \frac{x}{x^2 + y^2} \) and the imaginary part \( v = y - \frac{y}{x^2 + y^2} \).
The decomposition into real and imaginary components helps us analyze the properties and behaviors of the function more effectively. It's a way to break down complex problems into more manageable pieces.
- \( x \) is the real part
- \( y \) is the imaginary part
This results in the real part \( u = x + \frac{x}{x^2 + y^2} \) and the imaginary part \( v = y - \frac{y}{x^2 + y^2} \).
The decomposition into real and imaginary components helps us analyze the properties and behaviors of the function more effectively. It's a way to break down complex problems into more manageable pieces.
Reciprocal of a Complex Number
Finding the reciprocal of a complex number is like finding the number that when multiplied with the original, results in 1. Let's consider the complex number \( z = x + yi \):
The reciprocal is given by \( \frac{1}{z} = \frac{x - yi}{x^2 + y^2} \), with the real part \( \frac{x}{x^2 + y^2} \) and imaginary part \( - \frac{y}{x^2 + y^2} \).
Reciprocal operations are significant in complex analysis as they often simplify equations and make the complex arithmetic manageable.
In our exercise, the reciprocal of \( z \) plays a crucial role in forming the complete function \( f(z) = z + \frac{1}{z} \).
This ability to handle reciprocals enables complex functions to be flexible and adaptable across various mathematical contexts. It underlines the power and elegance of complex numbers in solving real-world problems.
The reciprocal is given by \( \frac{1}{z} = \frac{x - yi}{x^2 + y^2} \), with the real part \( \frac{x}{x^2 + y^2} \) and imaginary part \( - \frac{y}{x^2 + y^2} \).
Reciprocal operations are significant in complex analysis as they often simplify equations and make the complex arithmetic manageable.
In our exercise, the reciprocal of \( z \) plays a crucial role in forming the complete function \( f(z) = z + \frac{1}{z} \).
This ability to handle reciprocals enables complex functions to be flexible and adaptable across various mathematical contexts. It underlines the power and elegance of complex numbers in solving real-world problems.