मराठी

Algebraic Operations of Complex Numbers

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Topics

  • Sets and Relations
  • Functions
  • Complex Numbers 33
  • Sequences and Series
    • Concept of Sequences
    • Geometric Progression (G.P.)
    • General Term Or the nth Term of a G.P.
    • Sum of the First n Terms of a G.P.
    • Sum of Infinite Terms of a G. P.
    • Recurring Decimals
    • Harmonic Progression (H. P.)
    • Types of Means
    • Special Series (Sigma Notation)
  • Locus and Straight Line
    • Locus
    • Equation of Locus
    • Line
    • Equations of Lines in Different Forms
    • General Form Of Equation Of Line
  • Determinants
  • Limits
    • Definition of Limit of a Function
    • Algebra of Limits
    • Evaluation of Limits
    • Direct Method
    • Factorization Method
    • Rationalization Method
    • Limits of Exponential and Logarithmic Functions
  • Continuity
    • Continuous and Discontinuous Functions
    • Continuity of a Function at a Point
    • Definition of Continuity
    • Continuity from the Right and from the Left
    • Properties of Continuous Functions
    • Continuity in the Domain of the Function
    • Examples of Continuous Functions Whereever They Are Defined
  • Differentiation
    • The Meaning of Rate of Change
    • Definition of Derivative and Differentiability
    • Derivative by the Method of First Principle
    • Rules of Differentiation (Without Proof)
    • Applications of Derivatives
  • Partition Values
    • Concept of Median
    • Partition Values
    • Quartiles
    • Deciles
    • Percentiles
    • Relations Among Quartiles, Deciles and Percentiles
    • Graphical Location of Partition Values
  • Measures of Dispersion
    • Measures of Dispersion
    • Range of Data
    • Quartile Deviation (Semi - Inter Quartile Range)
    • Variance and Standard Deviation
    • Standard Deviation for Combined Data
    • Coefficient of Variation
  • Skewness
    • Skewness
    • Asymmetric Distribution (Positive Skewness)
    • Asymmetric (Negative Skewness)
    • Measures of Skewness
    • Karl Pearson’S Coefficient of Skewness (Pearsonian Coefficient of Skewness)
    • Features of Pearsonian Coefficient
    • Bowley’s Coefficient of Skewness
  • Bivariate Frequency Distribution and Chi Square Statistic
    • Bivariate Frequency Distribution
    • Classification and Tabulation of Bivariate Data
    • Marginal Frequency Distributions
    • Conditional Frequency Distributions
    • Categorical Variables
    • Contingency Table
    • Chi-Square Statistic ( χ2 )
  • Correlation
    • Correlation
    • Concept of Covariance
    • Properties of Covariance
    • Concept of Correlation Coefficient
    • Scatter Diagram
    • Interpretation of Value of Correlation Coefficient
  • Permutations and Combinations
    • Introduction of Permutations and Combinations
    • Fundamental Principles of Counting
    • Concept of Addition Principle
    • Concept of Multiplication Principle
    • Concept of Factorial Function
    • Permutations
    • Permutations When All Objects Are Distinct
    • Permutations When Repetitions Are Allowed
    • Permutations When All Objects Are Not Distinct
    • Circular Permutations
    • Properties of Permutations
    • Combination
    • Properties of Combinations
  • Probability
  • Linear Inequations
  • Commercial Mathematics
    • Percentage
    • Profit and Loss
    • Simple and Compound Interest (Entrance Exam)
    • Depreciation
    • Partnership
    • Goods and Service Tax (GST)
    • Shares and Dividends
  • Equality of two Complex Numbers 
  • Conjugate of a Complex Number 
  • Properties of `barz`
  • Addition of complex numbers - Properties of addition, Scalar Multiplication
  • Subtraction of complex numbers - Properties of Subtraction
  • Multiplication of complex numbers - Properties of Multiplication
  • Powers of i in the complex number
  • Division of complex number - Properties of Division
  • The square roots of a negative real number
  • Identities

Notes

1) Addition of two complex numbers : 
Let `z_1` = a + ib and `z_2` = c + id be any two complex numbers. Then, the sum  `z_1` + `z_2 `is defined as follows: 
`z_1` + `z_2` = (a + c) + i (b + d), which is again a complex number. 
For example, (2 + i3) + (– 6 +i5) = (2 – 6) + i (3 + 5) = – 4 + i 8
The addition of complex numbers satisfy the following properties: 
(i) The closure law  The sum of two complex numbers is a complex number, i.e., `z_1` + `z_2` is a complex number for all complex numbers `z_1` and `z_2`. 
(ii) The commutative law  For any two complex numbers `z_1` and `z_2`, `z_1` + `z_2` =` z_2` + `z_1` 
(iii) The associative law  For any three complex numbers `z_1, z_2, z_3, (z_1 + z_2) + z_3 = z_1 + (z_2 + z_3)`. 
(iv) The existence of additive identity  There exists the complex number 0 + i 0 (denoted as 0), called the additive identity or the zero complex number, such that, for every complex number z, z + 0 = z. 
(v) The existence of additive inverse  To every complex number z = a + ib, we have the complex number – a + i(– b) (denoted as –  z), called the additive inverse or negative of z. We observe that z + (–z) = 0 (the additive identity).

2) Difference of two complex numbers:
Given any two complex numbers `z_1` and `z_2`, the difference `z_1 – z_2` is defined as follows:
 z_1 – z_2 = z_1 + (– z_2). 
For example, (6 + 3i) – (2 – i) = (6 + 3i) + (– 2 + i ) = 4 + 4i 
and (2 –  i) – (6 + 3i) = (2 – i) + ( – 6 – 3i) = – 4 – 4i

3) Multiplication of two complex numbers:
Let `z_1` = a + ib and `z_2` = c + id be any two complex numbers. Then, the product `z_1 z_2` is defined as follows:
`z_1 z_2` = (ac –  bd) + i(ad + bc) For example, (3 + i5) (2 + i6) = (3 × 2 – 5 × 6) + i(3 × 6 + 5 × 2) = – 24 + i28 
The multiplication of complex numbers possesses the following properties, which we state without proofs. 
(i) The closure law :The product of two complex numbers is a complex number, the product `z_1 z_2` is a complex number for all complex numbers `z_1 and z_2`. 
(ii) The commutative law: For any two complex numbers `z_1` and `z_2, z_1 z_2 = z_2 z_1`. 
(iii) The associative law: For any three complex numbers `z_1, z_2, z_3, (z_1 z_2) z_3 = z_1 (z_2 z_3)`. 
(iv) The existence of multiplicative identity: There exists the complex number 1 + i 0 (denoted as 1),  called the multiplicative identity such that z.1 = z, for every complex number z. 
(v) The existence of multiplicative inverse: For every non-zero complex number z = a + ib or a + bi(a ≠ 0, b ≠ 0), we have the complex number `a/(a^2+b^2)` + i -`b/(a^2+b^2)` (denoted by `1/z or z^-1`), called the multiplicative inverse of z such that 
z,`1/z`= 1 (the multiplicative identity).
(vi) The distributive law: For any three complex numbers `z_1, z_2, z_3`, 
(a)  `z_1 (z_2 + z_3) = z_1 z_2 + z_1 z_3` 
(b) ` (z_1 + z_2) z_3 = z_1 z_3 + z_2 z_3`

4) Division of two complex numbers:  Given any two complex numbers `z_1` and  `z_2`,
where z_2 ≠ 0, the quotient `z_1/z_2` is defined by 
`z_1/z_2= z_1 1/z_2`
For example, let `z_1 `= 6 + 3i and ` z_2` = 2 – i
Then `z_1/z_2`= `[(6+3i)xx 1/(2-i)]`


= `(6+3i) [2/ [2^2+ (-1)^2] + i -(-1)/[2^2+(-1)^2]]`


= `(6+3i) [(2+i)/5]`


= `1/5 [12-3+i(6+6)]`


= `1/5 (9+12i)`


5) Power of i:
we know that 
`i^3= i^2i= (-1)i= -i,`
`i^4= (i^2)^2= (-1)^2= 1`
`i^5= (i^2)^2 i= (-1)^2 i= i,`
`i^6= (i^2)^3= (-1)^3= -1`, etc.
Also, we have `i^-1= (1/i) xx (i/i)= i/-1= -i,` 
`i^-2= 1/i^2= 1/-1= 1,` 
`i^-3= 1/i^3= (1/-i)xx (i/i)= i/1= i,` 
`i^-4= 1/i^4= 1/1= 1` 

In general, for any integer k, `i^(4k)=1, i^(4k+1)=i, i^(4k+2)= -1, i^(4k+3)= -i`

6) The square roots of a negative real number:
If a is a positive real number, `sqrt -a= sqrt a sqrt-1= sqrt a i,`
`sqrt a xx sqrt b= sqrt ab ` for all positive real number a and b. This result also holds true when either a > 0, b < 0  or a < 0,  b > 0. 
`sqrt a xx sqrt b ≠ sqrt ab` if both a and b are negative real numbers.
 If any of a and b is zero, then, `sqrt a xx sqrt b= sqrt ab = 0`

7) Identities:
1) `(z_1 + z_2)^2= z_1^2+ z_2^2+ 2z_1z_2`


2)` (z_1 -  z_2)^2= z_1^2- z_2^2+ 2z_1z_2`


3) `(z_1+ z_2)^3= z_1^3+ 3z_1^2z_2+ 3z_1z_2^2+ z_2^3`


4) `(z_1- z_2)^3= z_1^3- 3z_1^2z_2+ 3z_1z_2^2- z_2^3`


5) `z_1^2- z_2^2= (z_1+z_2) (z_1- z_2)`

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