Javascript quadratic equation solver

Here is a simple javascript that solves quadratic equations of the form ax²+bx+c = O. You just have to specify the values of a ,b and c and the script then calculates the two real roots alpha(x1) and beta (x2)  of the equation. The script also tells you if the equation has a real root or not, depending upon the value of D (Discriminant). The equation is solved using the quadratic formula x = -b±(b²-4ac)½/2a .
The script is located here ->

Here is the source code of the script :

//Place this within the  section
<script type="text/javascript"><
function calculate()
     var a=prompt("enter value of a");
     var b=prompt("enter value of b");
     var c=prompt("enter value of c");
     var a2=2*a;
     var ac=4*a*c;
     var dis=b*b;
     var dis=dis-ac;
        document.getElementById('Equation').innerHTML='No real roots exist since Discriminant < 0 !<br />D = ' + dis + ' <br />The Equation = ' + a + 'x&#178; + ' + b + 'x + ' + c + '<br />';
        document.getElementById('x1').innerHTML='&nbsp; ';
        document.getElementById('x2').innerHTML='&nbsp; ';
        var dis_sqrt=Math.sqrt(dis);
        var x1=-b+dis_sqrt;
        var x1=x1/a2;
        var x2=-b-dis_sqrt;
        var x2=x2/a2;
        document.getElementById('Equation').innerHTML=" Equation = " + a + "x&#178; + " + b + "x + " + c + "<br />";
        document.getElementById('x1').innerHTML=' Alpha (x1) = ' + x1;
        document.getElementById('x2').innerHTML=' Beta (x2) = ' + x2;

//Place this within the section:
<h1><a onclick="calculate()" href="#"> Click to solve »»</a></h1>
    <div id="Equation"></div>
    <div id="x1"></div>
    <div id="x2"></div>


One response to this entry

  • I’m not a SEO expert but you might want to cnhgae your CSS IDs to names like Navigation’ or Header’. I read awhile ago that that these get parsed by big daddy G.. and maybe with keywords like navigation.. the content in those divs might be ranked lower in context to other div IDs that might have the word content’ in them. Also, if you are using any HX tags in your navigation, you might want to consider switching them to a generic div with a class. HX tags get more weight.. so that might take some more focus away from the menu as well..I like the javascript trick though, I’ve seen some major css float tricks to accomplish the same thing.. but I never think of them as elegant.

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