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CAT 2025 » CAT Study Material » Data Interpretation and Logical Reasoning » Complex Numbers
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Complex Numbers

In this article, we will cover Complex numbers meaning, complex numbers formulas, Set of complex numbers. A complex number is made up of two numbers: one real and one imaginary. The concept of the two-dimensional complex plane is discussed in depth using a complex number and the horizontal and vertical axes for the real and imaginary parts, respectively.

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Complex numbers are made up of two components: a real number and an imaginary number. Complex numbers serve as the foundation for more complex math, such as algebra. They can be used in a variety of real-life situations, particularly in electronics and electromagnetism. Complex numbers are usually written as a + bi, with the real number first and the imaginary number last. 

Because any part of a complex number can be 0, any real or imaginary number can be considered one. Complex does not indicate difficult; it just implies that the two sorts of numbers combine to produce a complex, such as a housing complex  a collection of connected structures.

Complex numbers meaning

A complex number is the sum of two real and imaginary numbers. A complex number is denoted by the letter z and has the form a + ib. Both a and b are genuine numbers in this case. 

The value ‘a’ is known as the real component and is indicated by Re(z), while ‘b’ is known as the imaginary part and is denoted by Im (z). ib is also known as an imaginary number.

For examples: 2+3i, -5-8i

The letter i often known as the iota, is used to denote the imaginary component of a complex integer. Iota(i) is also useful for finding the square root of negative values.

Complex numbers formulas

The addition, subtraction, multiplication, and division formulas for natural numbers can likewise be applied to complex numbers. The details of the various arithmetic operations on complex numbers are listed below.

Complex Numbers Addition

Complex numbers can be added in the same way that natural numbers may. The real component of a complex number is added to the real part, and the imaginary part is added to the imaginary part. 

(a+bi) + (c+di) = (a+c) + (b+d)i 

Complex Number Subtraction

Subtracting complex numbers works in the same way as subtracting natural numbers. Subtraction is performed individually across the real part and then across the imaginary part for any two complex numbers.

(a+bi) – (c+di) = (a-c) + (b-d)i 

Complex Number Multiplication

Multiplication of complex numbers differs from multiplication of natural numbers in a few ways.

(a+bi) × (c+di) = (ac-bd) + (ad+bc)i 

The polar form of multiplication for complex numbers differs slightly from the previously discussed version. Multiply the absolute values of the two complex numbers and add their arguments to get the product of the two complex numbers.

Complex Numbers Division

The reciprocal of a complex number is used in the division of complex numbers.

(a+bi)/(c+di) = (a+bi×c-di)/(c+di×c-di) 

Set of complex numbers

The Latin capital letter C is presented in a double-struck font face to symbolise the set of complex numbers. The complex plane is used to depict the set of complex numbers, which extends the set of real numbers. Typically, the sign appears in the following expression:

x ∈ C

This phrase simply says that the variable x represents a number from the set of complex numbers.

Conclusion

In this article we learned that, the square root of a negative number is easily found using a complex number. Complex numbers, often known as imaginary numbers, are used in real-world applications such as electricity and quadratic equations. Imaginary integers appear in equations that do not contact the x axis in quadratic planes. In advanced calculus, imaginary numbers are especially valuable. And we also learned about set of complex number The set of complex numbers is defined as a+bi, where I is the square root of negative one and a and b are real integers. The set is represented by the symbol C, which is a double-struck Latin capital letter C.

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Frequently asked questions

Get answers to the most common queries related to the CAT Examination Preparation.

Is zero considered a complex number?

Ans. We can define zero as a complex number with a zero imaginary part, indicating that it is a rea...Read full

What does the set of complex numbers have as its symbol?

Ans. The complex plane will also be referred to as C...Read full

When you multiply complex conjugate, what happens?

Ans. The complex conjugate has a unique feature. Consider what occurs when a complex integer is mul...Read full

What is the difference between real and complex numbers?

Ans. Real numbers include complex numbers. Because certain negative real number ...Read full

Is it possible to divide a complex number?

Ans. The conjugate of the complex number in the denominator is multiplied by both the numerator and...Read full

Ans. We can define zero as a complex number with a zero imaginary part, indicating that it is a real number. Zero is also a complex number with a zero real element, indicating that it is an imaginary number. As a result, zero can be described as both real and complicated.

Ans. The complex plane will also be referred to as C. C is the standard symbol for the set of all complex numbers. For real variables, we will use x and y, and for complex variables, z and w.

Ans. The complex conjugate has a unique feature. Consider what occurs when a complex integer is multiplied by its complex conjugate. The answer is a purely real number, with no imaginary component. When a complex number is multiplied by its conjugate, the output is always a real number.

Ans. Real numbers include complex numbers. Because certain negative real number

s are difficult to compute, the negative sign is denoted by an iota i and this representation of numbers with i is referred to as a complex number. Finding the square root of a negative number, as well as the negative roots of a quadratic or polynomial equation, requires more complex quantities.

Ans. The conjugate of the complex number in the denominator is multiplied by both the numerator and denominator to divide complex numbers. This will enable us to acquire a real number in the denominator, as well as the division result.

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