Algebra

 ALGEBRA

Algebra is a branch of mathematics that uses variables, numbers, and mathematical operations to represent problems or situations in the form of mathematical expressions. 

Algebra involves manipulating abstract symbols, rather than numbers, with arithmetic. 

For example, x+y=z and b-2=5 are algebraic equations, but 2+3=5 and 73*46=3,358 are not.

In algebra, variables like x, y, and z have unknown values and may change. 

Mathematical operations like addition, subtraction, multiplication, and division are combined with variables to form a meaningful equation.

Algebra is a unifying thread of almost all of mathematics. 

Elementary algebra deals with the manipulation of variables as if they were numbers and is therefore essential in all applications of mathematics.

Algebra Of Complex Numbers

Complex numbers are algebraic expressions that contain the factor i=√-1. 
They are divided into two parts: the real part, denoted by Re(z), and the imaginary part, denoted by I(z)

For example, for a complex number z=2+3i, a=Re(z)=2 and b=Im(z)=3.
Here are some algebraic operations on complex numbers:
  • Z1 + z2=(a+ib)+(c+id)=(a+c)+i(b+d)
  • Z1 – z2 =(π‘Ž+𝑖𝑏)−(𝑐+𝑖𝑑)=(π‘Žb)+𝑖(𝑏𝑑)
  • 𝑧1𝑧2=𝑅𝑒(𝑧1−𝑧2)+πΌπ‘š(𝑧1−𝑧2)
  • Multiplication is defined as (π‘Ž,𝑏)×(𝑐,𝑑)=(π‘Žπ‘π‘π‘‘,π‘Žπ‘‘+𝑏𝑐)
  • Addition is defined as  (π‘Ž,𝑏)+(𝑐,𝑑)=(π‘Ž+𝑐,𝑏+𝑑)

Complex numbers are useful in electrical circuits, where it is customary to use 𝑗 for the imaginary unit.

Graphical representation of complex numbers


Complex numbers can be represented graphically as a point in a coordinate plane. The plane where a complex number is assigned to each of its points is called a complex plane, also known as an argand plane or argand diagram.

The x-axis becomes the real axis and the y-axis becomes the imaginary axis. For example, the complex number x+iy is represented as a point in Figure 2.2.1.

If the number is in polar coordinates, r represents the distance from the origin to the point, and ΞΈ represents the angle that r makes with the positive x-axis (measuring counterclockwise).

The modulus and argument of a complex number

The modulus and argument of a complex number are: 

 

Modulus and Argument - Newcastle University

The length of the line segment is called the modulus of the complex number and is denoted |z| . The angle measured from the positive real axis to the line segment is called the argument of the complex number, denoted arg(z) a r g ( z ) and often labelled ΞΈ .

 

Numeracy, Maths and Statistics - Academic Skills Kit

 

How to Find the Modulus and Argument of a Complex Number

12-Jun-2021 — Modulus: The modulus of a complex number z = a + b i is given by | z | = a 2 + b 2 . Argument: The argument of a complex number z = a + b i is given by ΞΈ = tan − 1 where − Ο€ < ΞΈ ≤ Ο€ .

 

Study.com

 

Modulus and Argument of a Complex Number - Unacademy

The argument of a complex number is the angle formed by the complex number with the positive axis of the argand plane, while the modulus of a complex number is its distance from the origin.

 

Unacademy

The modulus and argument of a complex number - Mathcentre

The length of the line segment, that is OP, is called the modulus of the complex number. The angle from the positive axis to the line segment is called the argument of the complex number, z. The modulus and argument are fairly simple to calculate using trigonometry. Example.

 

Mathcentre

 

Find the modulus and argument of the complex number

The argument $\theta ={{\tan }^{-1}}\left( \dfrac{b}{a} \right)$ is also called principal argument since tangent function is periodic and all other arguments are given by $n\pi +\theta $ where $n$ is any integer.

 

Vedantu

 

How to Find the Modulus and Argument of a Complex Number

14-Jan-2023 — number. we consider a general complex number Z equals a plus b. i on the complex axes. it is here with real component a and complex component B. now the modulus of Z means its length the modulus is written like so and it is equal to the square root of a squared plus b squared. this is the length of the line Z as calculated using Pythagoras's Theorem now the argument of Z is the angle measured from the positive real axis. for example the complex number shown has the argument measured from the positive real axis as shown.

 

m.youtube.com

  • Modulus

The length of the line segment from the origin to the complex number.

  • Argument

The angle is formed by the complex number with the positive axis of the argand plane.

The modulus and argument can be calculated using trigonometry.

The cube root of unity

The cube root of unity is a number that, when multiplied by itself three times, gives the product as 1. It is written as 3√1 and has three roots: 1, \omega, \omega^2.

When multiplied together, these three roots yield the answer unity. One of the roots is a real root, while the other two are imaginary roots:

  • 1 is the actual root
  • πœ” and πœ”2 are imaginary roots
The product of the imaginary roots of the cube root of unity is equal to 1, and the sum of the cube roots of unity is equal to zero:
  • πœ”⋅πœ”2=πœ”3=1
  • 1+πœ”+πœ”2=0

The values of the cube root of unity are:

  • 1
  • πœ”=−1+𝑖√3/2
  • πœ”2=−1−𝑖√3/2

=
i equals
 the square root of negative 1 end root

=
i equals
 the square root of negative 1 end root

Arithmetic

Arithmetic is a branch of mathematics that deals with operations on numbers. The four basic operations in arithmetic are: Addition, Subtraction, Multiplication, Division.

The order of these operations is given by the DMAS rule.

Arithmetic is derived from the Greek word arithmos, which means "number". It generally refers to the elementary aspects of the theory of numbers, arts of mensuration (measurement), and numerical computation.

Arithmetic is one of the important branches of mathematics that lays the foundation of the subject "Maths" for students. The first known use of arithmetic was in the 15th century.

An Indian mathematician and astronomer Brahmagupta is known as the Father of Arithmetic. 

What are the 5 arithmetic operators?

Here are some arithmetic operators:

  • Addition: (+)
  • Subtraction: (-)
  • Multiplication: (*)
  • Division: (/)
  • Modulo: (%)
  • Exponentiation: (^)
  • Increment: (++)
  • Decrement: (--)
  • Unary plus: (+)

Many programming languages support a combination of the assignment (=) and arithmetic operators. For example, in C, the arithmetic operators include:

Addition (+, Subtraction (-, Multiplication (*, Division (/, Modulo (%, Increment (++, Decrement (--, Unary plus (+. 

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