Roots of Quadratic Equation: C

Quadratic Equations are of the form ax2 + bx + c = 0. To find roots(root1 and root2) of such an equation, we need to use the formula

quadratic-equation


Find Roots of Quadratic Equation: C Program



YouTube Link: https://www.youtube.com/watch?v=zRcFm8AVV7k [Watch the Video In Full Screen.]


To calculate the roots of a quadratic equation in a C program, we need to break down the formula and calculate smaller parts of it and then combine to get the actual solution.

So lets calculate square root of b2 – 4 * a * c and store it in variable root_part. Also store 2 * a in variable denom. Now calculate ( – b + root_part ) / denom and store it in root1 and ( – b – root_part ) / denom in root2. Output the values of root1 and root2 to the console window.

Calculating Roots of Quadratic Equation In C

  1.    
  2. #include < stdio.h >  
  3. #include < math.h >  
  4.   
  5. int main()  
  6. {  
  7.     float a, b, c;  
  8.     float root1, root2;  
  9.     float root_part, denom;  
  10.   
  11.     printf("Enter values of a, b and c\n");  
  12.     scanf("%f%f%f", &a, &b, &c);  
  13.   
  14.     if(a == 0)  
  15.     {  
  16.         printf("If a is zero, equation becomes linear and not quadratic\n");  
  17.         printf("Please enter non-zero number for a\n");  
  18.     }  
  19.     else  
  20.     {  
  21.         root_part = sqrt(b * b - 4 * a * c);  
  22.         denom     = 2 * a;  
  23.   
  24.         root1     = ( - b + root_part ) / denom;  
  25.         root2     = ( - b - root_part ) / denom;  
  26.   
  27.         printf("Root1 = %f\nRoot2 = %f", root1, root2);  
  28.     }  
  29.   
  30.     return 0;  
  31. }  

Output 1
Enter values of a, b and c
1
4
4
Root1 = -2.000000
Root2 = -2.000000

Output 2
Enter values of a, b and c
0
4
4
If a is zero, equation becomes linear and not quadratic
Please enter non-zero number for a

Work Space: Cross Verification of Root values
Quadratic Equation: ax2 + bx + c = 0
Let,
a = 1
b = 4
c = 4
i.e., 1x2 + 4x + 4 =0
=> 1x2 + 2x + 2x + 4 = 0
=> x ( x + 2 ) + 2 ( x + 2 ) = 0
=> ( x + 2 ) + ( x + 2 ) = 0
=> x + 2 = 0 AND x + 2 = 0
=> x = -2 AND x = -2

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

Roots of Quadratic Equation: JavaScript

Quadratic Equations are of the form ax2 + bx + c = 0. To find roots(root1 and root2) of such an equation, we need to use the formula

quadratic-equation


Video Explaining The JavaScript Code To Find Roots of a Quadratic Equation:



YouTube Link: https://www.youtube.com/watch?v=Td6QViKdbZU [Watch the Video In Full Screen.]


To calculate the roots of a quadratic equation using a computer program, we need to break down the formula and calculate smaller parts of it and then combine to get the actual solution.

So lets calculate square root of b2 – 4 * a * c and store it in variable root_part. Also store 2 * a in variable denom. Now calculate ( – b + root_part ) / denom and store it in root1 and ( – b – root_part ) / denom in root2.
Output the values of root1 and root2 to the browser using document.write statement.

Javascript Coding Explained In Above Video:

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 <title>Quadratic Equation</title>
 
 
<script type="text/javascript">
<!--
var a = prompt("Enter value of a","1");
var b = prompt("Enter value of b","4");
var c = prompt("Enter value of c","4");
 
var root_part = Math.sqrt(b * b - 4 * a * c);
var denom = 2 * a;
 
var root1 = ( -b + root_part ) / denom;
var root2 = ( -b - root_part ) / denom;
 
document.write("1st root: "+root1+"<br />");
document.write("2nd root: "+root2+"<br />");
 
// -->
</script>

Usually people will make mistake in this line

var root_part = Math.sqrt(b * b - 4 * a * c);

Be sure that, you write capital letter M in Math.sqrt.

Work Space:
Quadratic Equation: ax2 + bx + c = 0
Let,
a = 1
b = 4
c = 4
i.e., 1x2 + 4x + 4 =0
=> 1x2 + 2x + 2x + 4 = 0
=> x ( x + 2 ) + 2 ( x + 2 ) = 0
=> ( x + 2 ) + ( x + 2 ) = 0
=> x + 2 = 0 AND x + 2 = 0
=> x = -2 AND x = -2