使用其空间对角线的体积

给定一个立方体的空间对角线长度d 。任务是计算给定空间对角线长度下立方体所占的体积。空间对角线是连接不在同一面上的两个顶点的线。

例子：

Input: d = 5 
Output: Volume of Cube: 24.0563

Input: d = 10
Output: Volume of Cube: 192.45

Volume of cube whose space diagonal is given: $\sqrt{3} \frac{d^3}{9}$

证明：

Let d = the length of diagonal |AB| and 
let a = the length of each side of the cube. 
Pythagorus #1 in triangle ACD: 
$(AC)^2=(a)^2+(a)^2 AC = \sqrt{2}a $$
Pythagorus #2 in triangle ABC: 
$(AB)^2=(\sqrt{2}a)^2+(a)^2 AB = \sqrt{3}a $$
Now we can solve for a in terms of d: 
$$$a=\frac{d}{ \sqrt{3} }$$
This means that the volume V is: 
$$V=a^3=\frac{d^3}{3 \sqrt{3}} = \frac{\sqrt{3}d^3}{9}$$$

以下是所需的实现：

C++

// C++ program to find the volume occupied
// by Cube with given space diagonal
#include 
using namespace std;
 
// Function to calculate Volume
float CubeVolume(float d)
{
    float Volume;
 
    // Formula to find Volume
    Volume = (sqrt(3) * pow(d, 3)) / 9;
 
    return Volume;
}
 
// Drivers code
int main()
{
 
    // space diagonal of Cube
    float d = 5;
 
    cout << "Volume of Cube: "
         << CubeVolume(d);
 
    return 0;
}

Java

// Java program to find the volume occupied
// by Cube with given space diagonal
 
public class GFG{
     
    // Function to calculate Volume
    static float CubeVolume(float d)
    {
        float Volume;
     
        // Formula to find Volume
        Volume = (float) (Math.sqrt(3) * Math.pow(d, 3)) / 9;
     
        return Volume;
    }
     
    // Drivers code
    public static void main(String []args)
    {
     
        // space diagonal of Cube
        float d = 5;
     
        System.out.println("Volume of Cube: " + CubeVolume(d));
     
    }
 
    // This code is contributed by Ryuga
    }

Python3

# Python 3 program to find the volume occupied
# by Cube with given space diagonal
from math import sqrt, pow
 
# Function to calculate Volume
def CubeVolume(d):
 
    # Formula to find Volume
    Volume = (sqrt(3) * pow(d, 3)) / 9
 
    return Volume
 
# Drivers code
if __name__ == '__main__':
 
    # space diagonal of Cube
    d = 5
 
    print("Volume of Cube:",'{0:.6}' .
                format(CubeVolume(d)))
 
# This code is contributed
# by SURENDRA_GANGWAR

C#

// C# program to find the volume occupied
// by Cube with given space diagonal
using System;
 
public class GFG{
     
    // Function to calculate Volume
    static float CubeVolume(float d)
    {
        float Volume;
     
        // Formula to find Volume
        Volume = (float) (Math.Sqrt(3) * Math.Pow(d, 3)) / 9;
     
        return Volume;
    }
     
    // Drivers code
    public static void Main()
    {
     
        // space diagonal of Cube
        float d = 5;
     
        Console.WriteLine("Volume of Cube: {0:F4}" , CubeVolume(d));
     
    }
 
    // This code is contributed by mits
    }

Javascript

 
// javascript program to find the volume occupied
// by Cube with given space diagonal
 
// Function to calculate Volume
function CubeVolume( d)
{
    let Volume;
 
    // Formula to find Volume
    Volume = (Math.sqrt(3) * Math.pow(d, 3)) / 9;
 
    return Volume;
}
 
// Drivers code
 
    // space diagonal of Cube
    let d = 5;
 
   document.write( "Volume of Cube: "
         + CubeVolume(d).toFixed(4));
          
// This code contributed by gauravrajput1
 

输出：

Volume of Cube: 24.0563

时间复杂度： O(1)