# Finding the Cotangent of Complex Number in Golang

Complex numbers are a fundamental concept in mathematics and are widely used in various fields such as physics, engineering, and computer science. In Go language, the math/cmplx package provides a set of functions to perform arithmetic operations on complex numbers. One such function is Cot, which calculates the cotangent of a complex number.

## Understanding Cotangent of Complex Number

The cotangent of a complex number is defined as the ratio of the cosine of the complex number to the sine of the complex number. It is represented mathematically as −

cot(z) = cos(z) / sin(z)


where z is the complex number.

## Syntax of Cot Function

The syntax of the Cot function in Go is −

func Cot(z complex128) complex128


Here, the function takes a complex number as input and returns the cotangent of that complex number.

## Example 1: Finding Cotangent of Complex Number

Let's say we have a complex number z = 2 + 3i. We can find the cotangent of this complex number using the Cot function as follows −

package main

import (
"fmt"
"math/cmplx"
)

func main() {
z := complex(2, 3)
cot := cmplx.Cos(z) / cmplx.Sin(z)
fmt.Println("cot(", z, ") = ", cot)
}


## Output

cot( (2+3i) ) =  (-0.003739710376336852-0.9967577965693585i)


In the above example, we first create a complex number z using the complex function. Then, we use the Cot formula to calculate the cotangent of this complex number. Finally, we print the cotangent value using the fmt.Println function.

## Example 2: Finding Cotangent of Another Complex Number

Let's take another complex number z = 1 + 2i and find its cotangent value.

package main

import (
"fmt"
"math/cmplx"
)

func main() {
z := complex(1, 2)
cot := cmplx.Cos(z) / cmplx.Sin(z)
fmt.Println("cot(", z, ") = ", cot)
}


## Output

cot( (1+2i) ) =  (0.032797755533752464-0.9843292264581909i)


## Example 3: Finding Cotangent of Zero

Let's take a complex number z = 0 and find its cotangent value.

package main

import (
"fmt"
"math/cmplx"
)

func main() {
z := complex(0, 0)
cot := cmplx.Cos(z) / cmplx.Sin(z)
fmt.Println("cot(", z, ") = ", cot)
}


## Output

cot( (0+0i) ) =  (+Inf+NaNi)


In the above example, we take a complex number z = 0 and find its cotangent value using the Cot formula. The reason for this output is that the cotangent of zero is undefined, and the math/cmplx package in Go follows the IEEE 754 standard for handling such cases. According to this standard, dividing by zero results in positive or negative infinity, depending on the sign of the operands. In this case, the real part of the result is positive infinity (+Inf) and the imaginary part is NaN (Not a Number), indicating that the result is undefined.

## Conclusion

In this article, we have seen how to find the cotangent of a complex number in Go language using the Cot function provided by the math/cmplx package. We have also seen some examples of finding the cotangent value of different complex numbers, including zero.

Updated on: 12-Apr-2023

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