Go language provides inbuilt support for basic constants and mathematical functions to perform operations on the numbers with the help of the math package. You are allowed to find the arccosine of the specified number with the help of Acos() function provided by the math package. So, you need to add a math package in your program with the help of the import keyword to access the Acos() function.
func Acos(y float64) float64
If the value of y < -1 or y > 1, then Acos(y) = NaN
Result 1: 0.0 Result 2: 3.1 Result 3: NaN
0.0 + 3.1 = 3.1