# Finding the Inverse Cosine of Complex Number in Golang

• Last Updated : 26 Mar, 2020

Go language provides inbuilt support for basic constants and mathematical functions for complex numbers with the help of the cmplx package. You are allowed to find the inverse cosine of the specified complex number with the help of Acos() function provided by the math/cmplx package. So, you need to add a math/cmplx package in your program with the help of the import keyword to access the Acos() function.

Syntax:

`func Acos(x complex128) complex128`

Let us discuss this concept with the help of the given examples:

Example 1 :

 `// Golang program to illustrate``// how to find inverse cosine of``// complex number``package main`` ` `import (``    ``"fmt"``    ``"math/cmplx"``)`` ` `// Main function``func main() {`` ` `    ``// Finding inverse cosine of the``    ``// specified complex number``    ``// Using Acos() function``    ``res_1 := cmplx.Acos(3 + 5i)``    ``res_2 := cmplx.Acos(-4 + 8i)``    ``res_3 := cmplx.Acos(-8 - 7i)`` ` `    ``// Displaying the result``    ``fmt.Println(``"Result 1:"``, res_1)``    ``fmt.Println(``"Result 2:"``, res_2)``    ``fmt.Println(``"Result 3:"``, res_3)``}`

Output:

```Result 1: (1.0367972572007265-2.4598315216234306i)
Result 2: (2.031957962047241-2.886039504947561i)
Result 3: (2.4205679446613617+3.0565545070216835i)
```

Example 2 :

 `// Golang program to illustrate how to find``// Inverse Cosine of Complex Number``package main`` ` `import (``    ``"fmt"``    ``"math/cmplx"``)`` ` `// Main function``func main() {`` ` `    ``cnumber_1 := complex(5, 7)``    ``cnumber_2 := complex(6, 9)`` ` `    ``// Finding inverse cosine``    ``cvalue_1 := cmplx.Acos(cnumber_1)``    ``cvalue_2 := cmplx.Acos(cnumber_2)`` ` `    ``// Sum of two inverse cosine values``    ``res := cvalue_1 + cvalue_2`` ` `    ``// Displaying results``    ``fmt.Println(``"Complex Number 1: "``, cnumber_1)``    ``fmt.Println(``"Inverse Cosine 1: "``, cvalue_1)`` ` `    ``fmt.Println(``"Complex Number 2: "``, cnumber_2)``    ``fmt.Println(``"Inverse Cosine 2: "``, cvalue_2)``    ``fmt.Println(``"Final sum: "``, res)`` ` `}`

Output:

```Complex Number 1:  (5+7i)
Inverse Cosine 1:  (0.9537320301189085-2.846288828208389i)
Complex Number 2:  (6+9i)
Inverse Cosine 2:  (0.9847612348751953-3.075060767946888i)
Final sum:  (1.9384932649941038-5.921349596155277i)
```

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