计算判别值

在代数中， D判别式可以帮助我们推导多项式或多项式函数的根的各种属性，甚至无需对其进行计算。让我们看一下这个二阶一般的二次多项式：

ax2 + bx + c

这里，使用以下公式计算方程的判别式：

b2 – 4ac

现在我们可以推断出以下属性：

• 如果判别式等于零，则多项式具有相等的根，即a = b。
• 如果判别式为正，系数为实，则多项式具有两个实根。

在进行编程并从判别式推论时，我们必须牢记以下几个条件：

• 如果判别式等于零，则一种解决方案是可能的。
• 如果判别结果为肯定，则可能有两种解决方案。
• 如果判别结果是否定的，则不可能有实际的解决方案。

例子：

Input:
a = 20
b = 30
c = 10
Explanation:
(30**2) - (4*20*10) 
Output:
Discriminant is 100 which is positive
Hence Two solutions

Input:
a = 9
b = 7
c = 12
Explanation:
(30**2) - (4*20*10) 
Output:
Discriminant is -383 which is negative
Hence no real solutions

C++

// CPP program to calculate Discriminant
#include 
 
using namespace std;
 
void discriminant(int a, int b, int c){
 
    int discriminant = (b*b) - (4*a*c);
    if(discriminant > 0){
        cout<<"Discriminant is "<

---

Java

// Java program to calculate discriminant
public class Discriminant{
     
    // function to calculate discriminant
    static int disc(int a, int b, int c){
        int dis = (int)Math.pow(b,2) - (4*a*c);
        return dis;
    }
 
    // Driver Code
    public static void main(String args[]){
        int a=20;
        int b=30;
        int c=10;
        int discriminant = disc(a, b, c);
        if (discriminant > 0){
            System.out.println("Discriminant is " + discriminant
                    + " which is Positive");
            System.out.println("Hence Two Solutions");
        }
        else if (discriminant == 0){
            System.out.println("Discriminant is " + discriminant
                    + " which is Zero");
            System.out.println("Hence One Solution");
        }
        else {
            System.out.println("Discriminant is "+ discriminant
                    + " which is Negative");
            System.out.println("Hence No Real Solutions");
        }
    }
}

Python3

# Python program to calculate Discriminant
 
def discriminant(a, b, c):
 
    discriminant = (b**2) - (4*a*c)
    if discriminant > 0:
         
        print('Discriminant is', discriminant,
                "which is Positive")
                 
        print('Hence Two Solutions')
         
    elif discriminant == 0:
         
        print('Discriminant is', discriminant,
                "which is Zero")
                 
        print('Hence One Solution')
         
    elif discriminant < 0:
         
        print('Discriminant is', discriminant,
                "which is Negative")
                 
        print('Hence No Real Solutions')
 
# Driver Code
a = 20
b = 30
c = 10
discriminant(a, b, c)

C#

// C# program to calculate
// discriminant
using System;
 
class GFG
{
 
// function to calculate
// discriminant
static int disc(int a,
                int b, int c)
{
    int dis = (int)Math.Pow(b, 2) -
                    (4 * a * c);
    return dis;
}
     
// Driver Code
public static void Main()
{
    int a = 20;
    int b = 30;
    int c = 10;
    int discriminant = disc(a, b, c);
    if (discriminant > 0)
    {
        Console.WriteLine("Discriminant is " +
                                discriminant +
                        " which is Positive");
        Console.WriteLine("Hence Two Solutions");
    }
     
    else if (discriminant == 0)
    {
        Console.WriteLine("Discriminant is " +
                                discriminant +
                            " which is Zero");
        Console.WriteLine("Hence One Solution");
    }
     
    else
    {
        Console.WriteLine("Discriminant is "+
                            discriminant +
                    " which is Negative");
        Console.WriteLine("Hence No Real Solutions");
    }
}
}
 
// This code is contributed
// by anuj_67.

PHP

 0)
    {
        echo "Discriminant is ", $discriminant,
             " which is Positive\n";
        echo "Hence Two Solutions";
    }
     
    else if($discriminant == 0)
    {
        echo "Discriminant is ", $discriminant,
             " which is Zero\n";
        echo "Hence One Solution";
    }
     
    else if($discriminant < 0)
    {
        echo "Discriminant is ", $discriminant,
             " which is Negative\n";
             
        echo "Hence No Real Solutions";
    }
}
 
// Driver code
$a = 20;
$b = 30;
$c = 10;
 
// function call to print discriminant
discriminant($a, $b, $c);
 
// This code is contributed
// by Shashank_Sharma
?>

Javascript

// javascript program to calculate discriminant
 
    // function to calculate discriminant
    function disc(a , b , c) {
        var dis = parseInt( Math.pow(b, 2) - (4 * a * c));
        return dis;
    }
 
    // Driver Code
     
        var a = 20;
        var b = 30;
        var c = 10;
        var discriminant = disc(a, b, c);
        if (discriminant > 0) {
            document.write("Discriminant is " + discriminant + " which is Positive<br/>");
            document.write("Hence Two Solutions");
        } else if (discriminant == 0) {
            document.write("Discriminant is " + discriminant + " which is Zero<br/>");
            document.write("Hence One Solution");
        } else {
            document.write("Discriminant is " + discriminant + " which is Negative<br/>");
            document.write("Hence No Real Solutions");
        }
 
// This code is contributed by todaysgaurav
 

输出：

Discriminant is 100 which is Positive
Hence Two Solutions