print (Mathf.Atan(0.5));

using UnityEngine;
using System.Collections;

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

import UnityEngine
import System.Collections

class example(MonoBehaviour):

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