# Complex number calculator

**Rectangular form:**

*z*= -3+2.5

**i**

**Angle notation (phasor):**

*z*= 3.9051248 ∠ 140°11'40″

**Polar form:**

*z*= 3.9051248 × (cos 140°11'40″ +

**i**sin 140°11'40″)

**Exponential form:**

*z*= 3.9051248 ×

**e**

^{i 0.7788579}

**Polar coordinates:**

r = |

*z*| = 3.9051248 ... magnitude (modulus, absolute value)

θ = arg

*z*= 2.4468544 rad = 140.19443° = 140°11'40″ = 0.7788579π rad ... angle (argument or phase)

**Cartesian coordinates:**

Cartesian form of imaginary number:

*z*= -3+2.5

**i**

Real part: x = Re

*z*= -3

Imaginary part: y = Im

*z*= 2.5

### Calculation steps

- Divide: -1 / 2 = -0.5
- Complex number: 6-5
**i** - Multiple: the result of step No. 1 * the result of step No. 2 = -0.5 * (6-5
**i**) = -0.5 * 6(-0.5) * (-5**i**) = -3+2.5**i**= -3 +**i**(2.5) = -3+2.5**i**

This calculator does basic arithmetic on complex numbers and evaluates expressions in the set of complex numbers. As imaginary unit use

Complex numbers in the angle notation or phasor (

Example of multiplication of two imaginary numbers in the angle/polar/phasor notation: 10L45 * 3L90.

Why the next complex numbers calculator when we have WolframAlpha? Because Wolfram tool is slow and some features such as step by step are charged premium service.

For use in education (for example, calculations of alternating currents at high school), you need a quick and precise complex number calculator.

**i**or**j**(in electrical engineering), which satisfies basic equation**i**or^{2}= −1**j**. The calculator also converts a complex number into angle notation (phasor notation), exponential, or polar coordinates (magnitude and angle). Enter expression with complex numbers like 5*(1+i)(-2-5i)^2^{2}= −1Complex numbers in the angle notation or phasor (

**polar coordinates**r, θ) may you write as**rLθ**where**r**is magnitude/amplitude/radius, and**θ**is the angle (phase) in degrees, for example, 5L65 which is the same as 5*cis(65°).Example of multiplication of two imaginary numbers in the angle/polar/phasor notation: 10L45 * 3L90.

Why the next complex numbers calculator when we have WolframAlpha? Because Wolfram tool is slow and some features such as step by step are charged premium service.

For use in education (for example, calculations of alternating currents at high school), you need a quick and precise complex number calculator.

## Basic operations with complex numbers

We hope that work with the complex number is quite easy because you can work with imaginary unit**i**as a variable. And use definition

**i**to simplify complex expressions. Many operations are the same as operations with two-dimensional vectors.

^{2}= -1### Addition

Very simple, add up the real parts (without i) and add up the imaginary parts (with i):This is equal to use rule: (a+b

**i**)+(c+d

**i**) = (a+c) + (b+d)

**i**

(1+i) + (6-5i) = 7-4

**i**

12 + 6-5i = 18-5

**i**

(10-5i) + (-5+5i) = 5

### Subtraction

Again very simple, subtract the real parts and subtract the imaginary parts (with i):This is equal to use rule: (a+b

**i**)+(c+d

**i**) = (a-c) + (b-d)

**i**

(1+i) - (3-5i) = -2+6

**i**

-1/2 - (6-5i) = -6.5+5

**i**

(10-5i) - (-5+5i) = 15-10

**i**

### Multiplication

To multiply two complex numbers, use distributive law, avoid binomials, and apply**i**.

^{2}= -1This is equal to use rule: (a+b

**i**)(c+d

**i**) = (ac-bd) + (ad+bc)

**i**

(1+i) (3+5i) = 1*3+1*5i+i*3+i*5i = 3+5i+3i-5 = -2+8

**i**

-1/2 * (6-5i) = -3+2.5

**i**

(10-5i) * (-5+5i) = -25+75

**i**

### Division

The division of two complex numbers can be accomplished by multiplying the numerator and denominator by the complex conjugate of the denominator. This avoid imaginary unit**i**from the denominator. If the denominator is c+d

**i**, to make it without i (or make it real), just multiply with conjugate c-d

**i**:

(c+d

**i**)(c-d

**i**) = c

^{2}+d

^{2}

$\dfrac{a+bi}{c+di} = \dfrac{(a+bi)(c-di)}{(c+di)(c-di)} = \dfrac{ac+bd+i(bc-ad)}{c^2+d^2} = \dfrac{ac+bd}{c^2+d^2}+\dfrac{bc-ad}{c^2+d^2} i$

(10-5i) / (1+i) = 2.5-7.5

**i**

-3 / (2-i) = -1.2-0.6

**i**

6i / (4+3i) = 0.72+0.96

**i**

### Absolute value or modulus

The absolute value or modulus is the distance of the image of a complex number from the origin in the plane. The calculato uses the Pythagorean theorem to find this distance. Very simple, see examples: |3+4i| = 5|1-i| = 1.4142136

|6i| = 6

abs(2+5i) = 5.3851648

### Square root

Square root of complex number (a+bi) is z, if z^{2}= (a+bi). Here ends simplicity. Because of the fundamental theorem of algebra, you will always have two different square roots for a given number. If you want to find out the possible values, the easiest way is probably to go with De Moivre's formula. Here our calculator is on edge, because square root is not a well defined function on complex number. We calculate all complex roots from any number - even in expressions:

sqrt(9i) = 2.1213203+2.1213203

**i**

sqrt(10-6i) = 3.2910412-0.9115656

**i**

pow(-32,1/5)/5 = -0.4

pow(1+2i,1/3)*sqrt(4) = 2.439233+0.9434225

**i**

pow(-5i,1/8)*pow(8,1/3) = 2.3986959-0.4771303

**i**

### Square, power, complex exponentiation

Our calculator can power any complex number to any integer (positive, negative), real, or even complex number. In other words, we calculate 'complex number to a complex power' or 'complex number raised to a power'...Famous example:

$i^i = e^{-\pi/2}$

i^2 = -1i^61 =

**i**

(6-2i)^6 = -22528-59904

**i**

(6-i)^4.5 = 2486.1377428-2284.5557378

**i**

(6-5i)^(-3+32i) = 2929449.03994-9022199.58262

**i**

i^i = 0.2078795764

pow(1+i,3) = -2+2

**i**

### Functions

- sqrt
- Square Root of a value or expression.
- sin
- the sine of a value or expression. Autodetect radians/degrees.
- cos
- the cosine of a value or expression. Autodetect radians/degrees.
- tan/tg
- tangent of a value or expression. Autodetect radians/degrees.
- exp
- e (the Euler Constant) raised to the power of a value or expression
- pow
- Power one complex number to another integer/real/complex number
- ln
- The natural logarithm of a value or expression
- log
- The base-10 logarithm of a value or expression
- abs or |1+i|
- The absolute value of a value or expression
- phase
- Phase (angle) of a complex number
- cis
- is less known notation: cis(x) = cos(x)+ i sin(x); example: cis (pi/2) + 3 = 3+
**i** - conj
- conjugate of complex number - example: conj(4i+5) = 5-4
**i**

#### Examples:

• cube root: cuberoot(1-27i)• roots of Complex Numbers: pow(1+i,1/7)

• phase, complex number angle: phase(1+i)

• cis form complex numbers: 5*cis(45°)

• The polar form of complex numbers: 10L60

• complex conjugate calculator: conj(4+5i)

• equation with complex numbers: (z+i/2 )/(1-i) = 4z+5i

• system of equations with imaginary numbers: x-y = 4+6i; 3ix+7y=x+iy

• De Moivre's theorem - equation: z^4=1

• multiplication of three complex numbers: (1+3i)(3+4i)(−5+3i)

• Find the product of 3-4i and its conjugate.: (3-4i)*conj(3-4i)

• operations with complex numbers: (3-i)^3

## Complex numbers in word problems:

- Let z1=x1+y1i

Let z1=x1+y1i and z2=x2+y2i Find: a = Im (z1z2) b = Re (z1/z2)

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