Mathf.Acos

static function Acos (f : float) : float

Description

Returns the arc-cosine of f - the angle in radians whose cosine is f.

JavaScript
    print (Mathf.Acos(0.5));

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void Example() {
print(Mathf.Acos(0.5F));
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def Example():
print(Mathf.Acos(0.5F))