Calculate A, where A = [2-i 3+2i 4 -i Calculate 2-4i|. Prove that for any complex numbers x and y, (xy) = (x)(y) and x+y=x+y.
Calculate A, where A = [2-i 3+2i 4 -i Calculate 2-4i|. Prove that for any complex numbers x and y, (xy) = (x)(y) and x+y=x+y.
Algebra & Trigonometry with Analytic Geometry
13th Edition
ISBN:9781133382119
Author:Swokowski
Publisher:Swokowski
Chapter8: Applications Of Trigonometry
Section8.5: Trigonometric Form For Complex Numbers
Problem 24E
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![### Problem 10
#### Complex Conjugate and Modulus
The **conjugate** of a complex number \( z = a + bi \) is \( a - bi \). We denote the conjugate by \( \overline{z} \).
We also define the **modulus** of a complex number \( z \), denoted by \( |z| \), as \( \sqrt{z\overline{z}} \). Note that \( z \overline{z} \) is always a nonnegative real number, so this is also a nonnegative real number.
#### Matrix Conjugate
Let \( A \) be a complex \( n \times n \) matrix, where \( n \ge 2 \). We define the matrix \( \overline{A} \) to be the matrix obtained by taking the conjugate of every entry of \( A \).
#### Questions
a. Calculate \( \overline{A} \), where \( A = \begin{bmatrix} 2 - i & 3 + 2i \\ 4 & -i \end{bmatrix} \).
b. Calculate \( |2 - 4i| \).
c. Prove that for any complex numbers \( x \) and \( y \), \( \overline{xy} = \overline{x} \overline{y} \) and \( \overline{x + y} = \overline{x} + \overline{y} \).
d. Prove that \( |yz| = |y||z| \) for any \( y, z \in \mathbb{C} \).
e. Prove that \( \det \overline{A} = \overline{\det A} \). (Hint: Show the \( 2 \times 2 \) case and use induction on \( n \).)
f. A **unitary matrix** \( A \in M_{n \times n}(\mathbb{C}) \) is one where \( \overline{A^T} = A^{-1} \). Prove that if \( A \) is a unitary matrix, then \( |\det A| = 1 \).
#### Explanations of Terms and Concepts
- **Complex Conjugate \( \overline{z} \)**: The conjugate of a complex number \( z = a](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F833bf7b1-3e6b-4749-8e88-54090320a3f5%2Fc3fdc8d1-8f96-485c-bb90-f94c38f2a510%2Fw3ohhsn_processed.png&w=3840&q=75)
Transcribed Image Text:### Problem 10
#### Complex Conjugate and Modulus
The **conjugate** of a complex number \( z = a + bi \) is \( a - bi \). We denote the conjugate by \( \overline{z} \).
We also define the **modulus** of a complex number \( z \), denoted by \( |z| \), as \( \sqrt{z\overline{z}} \). Note that \( z \overline{z} \) is always a nonnegative real number, so this is also a nonnegative real number.
#### Matrix Conjugate
Let \( A \) be a complex \( n \times n \) matrix, where \( n \ge 2 \). We define the matrix \( \overline{A} \) to be the matrix obtained by taking the conjugate of every entry of \( A \).
#### Questions
a. Calculate \( \overline{A} \), where \( A = \begin{bmatrix} 2 - i & 3 + 2i \\ 4 & -i \end{bmatrix} \).
b. Calculate \( |2 - 4i| \).
c. Prove that for any complex numbers \( x \) and \( y \), \( \overline{xy} = \overline{x} \overline{y} \) and \( \overline{x + y} = \overline{x} + \overline{y} \).
d. Prove that \( |yz| = |y||z| \) for any \( y, z \in \mathbb{C} \).
e. Prove that \( \det \overline{A} = \overline{\det A} \). (Hint: Show the \( 2 \times 2 \) case and use induction on \( n \).)
f. A **unitary matrix** \( A \in M_{n \times n}(\mathbb{C}) \) is one where \( \overline{A^T} = A^{-1} \). Prove that if \( A \) is a unitary matrix, then \( |\det A| = 1 \).
#### Explanations of Terms and Concepts
- **Complex Conjugate \( \overline{z} \)**: The conjugate of a complex number \( z = a
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