Auf Thema antworten

Beitrag

[QUOTE="Alexander M, post: 14709, member: 5177"]
Hello everyone,
I have a task in which I would like to implement the graphical visualisation of a quadratic equation in the interval x =[-10,10] and - if any exist - the corresponding zeros, using CanvasRenderingContext2D methods.
To convert the coordinates into pixel coordinates within the canvas: the coordinates into pixel coordinates within the canvas I would use following functions:
var toCanvasX  =  function (x)  {
return (x + (max-min ) / 2 ) * canvas.width /( max - min ); 
}
var toCanvasY  =  function (y)  {
return canvas.height - (y + (max-min ) / 2 ) * canvas.height / ( max - min); 
}
The graph should look like this:
 
[ATTACH type="full" alt="1715260333877.png"]524[/ATTACH]
[ATTACH type="full" alt="1715260333891.png"]523[/ATTACH]
How can I solve it? 
Code:
[CODE=html]<!DOCTYPE html>
<html>
 
<head>
    <meta charset="UTF-8">
    <h1>Solver of Quadratic Equations</h1>
    <script>
        var a, b, c;
        var output;
        
        function check() {
        
            
            a = document.forms["input_form"]["anumber"].value;
            b = document.forms["input_form"]["bnumber"].value;
            c = document.forms["input_form"]["cnumber"].value;
            
            
            if (a == 0) {
                output = "a cannot equal zero!";
            } else if (isNaN(a)) {
                output = "a has to be a number!";
            } else if (isNaN(b)) {
                output = "b has to be a number!";
            } else if (isNaN(c)) {
                output = "c has to be a number!";
            } else {
              
                var x1 = (-b - Math.sqrt(Math.pow(b, 2) - 4 * a * c)) / (2 * a);
                var x2 = (-b + Math.sqrt(Math.pow(b, 2) - 4 * a * c)) / (2 * a);
                output = "The polynomial <strong>" + (a == 1 ? "" : a) + "x\u00B2 + " + (b == 1 ? "" : b) + "x + " + c + " = 0</strong> has two zeros x1=" + x1 + "," + " " + "x2=" + x2;
            }
            
            document.getElementById("output").innerHTML = output;
        }
    </script>
</head>
 
<body>
 
    This programme calculates zeros of quadratic polynomials of the form ax² + bx + c and graphically displays the solution in the interval x ∈ [-10,10].
    <br><br>
    <form name="input_form" action="javascript:check();">
        a: <input type="text" name="anumber" required>
        b: <input type="text" name="bnumber" required>
        c: <input type="text" name="cnumber" required>
        <br><br>
        <input type="submit" value="Calculate zeros">
    </form>
    
    <p id="output"/>
 
</body>
 
</html>[/CODE]
[/QUOTE]

Authentifizierung