<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title></title>
<body>
<div align="center">例如输入：a=3, b=6, c=-123, d=-126 e=1080</div>
<form name="form1" action="">
ax<sup>4</sup> + bx<sup>3</sup> + cx<sup>2</sup> + dx + e = 0
<table border="0" align="center" colspan="4" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td><input type="text" name="aIn" size="5" placeholder="a">x<sup>4</sup> +</td>
<td><input type="text" name="bIn" size="5" placeholder="b">x³ +</td>
<td><input type="text" name="cIn" size="5" placeholder="c">x² +</td>
<td><input type="text" name="dIn" size="5" placeholder="d">x +</td>
<td><input type="text" name="eIn" size="5" placeholder="e">e</td>
</tr>
</tbody>
</table>
<center>
<input type="button" name="button1" value="计算" onclick="quad4solve(this.form)">
</center>
<table border="0" class="innerc" cellspacing="0" cellpadding="3">
<tbody>
<tr align="center">
<td class="inner" colspan="4"><b>结果：</b></td>
</tr>
<tr>
<td>x<sub>1</sub>:
<input type="text" name="x1Re" size="25"> +
<input type="text" name="x1Im" size="25"> i
</td>
</tr>
<tr>
<td>x<sub>2</sub>:
<input type="text" name="x2Re" size="25"> +
<input type="text" name="x2Im" size="25"> i
</td>
</tr>
<tr>
<td>x<sub>3</sub>:
<input type="text" name="x3Re" size="25"> +
<input type="text" name="x3Im" size="25"> i
</td>
</tr>
<tr>
<td>x<sub>4</sub>:
<input type="text" name="x4Re" size="25"> +
<input type="text" name="x4Im" size="25"> i
</td>
</tr>
</tbody>
</table>
</form>
<script type="text/javascript">
function quad4solve(dataForm)
{
var a = parseFloat(dataForm.aIn.value);
var b = parseFloat(dataForm.bIn.value);
var c = parseFloat(dataForm.cIn.value);
var d = parseFloat(dataForm.dIn.value);
var e = parseFloat(dataForm.eIn.value);
if (a == 0)
{
alert("The coefficient of the power four of x is 0. Please use the utility for a third degree quadratic.");
return;
}
if (e == 0)
{
alert("One root is 0. Now divide through by x and use the utility for a third degree quadratic to solve the resulting equation for the other three roots.");
return;
}
if (a != 1)
{
b /= a;
c /= a;
d /= a;
e /= a;
}
//立方解算器系数
var cb, cc, cd;
var discrim, q, r, RRe, RIm, DRe, DIm, dum1, ERe, EIm, s, t, term1, r13, sqR, y1, z1Re, z1Im, z2Re;
cb = -c;
cc = -4.0*e + d*b;
cd = -(b*b*e + d*d) + 4.0*c*e;
if (cd == 0)
{
alert("cd = 0.");
}
q = (3.0*cc - (cb*cb))/9.0;
r = -(27.0*cd) + cb*(9.0*cc - 2.0*(cb*cb));
r /= 54.0;
discrim = q*q*q + r*r;
term1 = (cb/3.0);
if (discrim > 0)
{
// 1 实数, 2 复数
s = r + Math.sqrt(discrim);
s = ((s < 0) ? -Math.pow(-s, (1.0/3.0)) : Math.pow(s, (1.0/3.0)));
t = r - Math.sqrt(discrim);
t = ((t < 0) ? -Math.pow(-t, (1.0/3.0)) : Math.pow(t, (1.0/3.0)));
y1 = -term1 + s + t;
}
else
{
if (discrim == 0)
{
r13 = ((r < 0) ? -Math.pow(-r,(1.0/3.0)) : Math.pow(r,(1.0/3.0)));
y1 = -term1 + 2.0*r13;
}
else
{
q = -q;
dum1 = q*q*q;
dum1 = Math.acos(r/Math.sqrt(dum1));
r13 = 2.0*Math.sqrt(q);
y1 = -term1 + r13*Math.cos(dum1/3.0);
}
}
// 确定了y1 分解立方的实根
term1 = b/4.0;
sqR = -c + term1*b + y1;
RRe = RIm = DRe = DIm = ERe = EIm = z1Re = z1Im = z2Re = 0;
if (sqR >= 0)
{
if (sqR == 0)
{
dum1 = -(4.0*e) + y1*y1;
if (dum1 < 0){
z1Im = 2.0*Math.sqrt(-dum1);
} else {
z1Re = 2.0*Math.sqrt(dum1);
z2Re = -z1Re;
}
}
else
{
RRe = Math.sqrt(sqR);
z1Re = -(8.0*d + b*b*b)/4.0 + b*c;
z1Re /= RRe;
z2Re = -z1Re;
}
}
else
{
RIm = Math.sqrt(-sqR);
z1Im = -(8.0*d + b*b*b)/4.0 + b*c;
z1Im /= RIm;
z1Im = -z1Im;
}
z1Re += -(2.0*c + sqR) + 3.0*b*term1;
z2Re += -(2.0*c + sqR) + 3.0*b*term1;
//At this point, z1 and z2 should be the terms under the square root for D and E
if (z1Im == 0)
{ // Both z1 and z2 real
if (z1Re >= 0)
{
DRe = Math.sqrt(z1Re);
}
else
{
DIm = Math.sqrt(-z1Re);
}
if (z2Re >= 0)
{
ERe = Math.sqrt(z2Re);
}
else
{
EIm = Math.sqrt(-z2Re);
}
}
else
{
r = Math.sqrt(z1Re*z1Re + z1Im*z1Im);
r = Math.sqrt(r);
dum1 = Math.atan2(z1Im, z1Re);
dum1 /= 2; //Divide this angle by 2
ERe = DRe = r*Math.cos(dum1);
DIm = r*Math.sin(dum1);
EIm = -DIm;
}
dataForm.x1Re.value = -term1 + (RRe + DRe)/2;
dataForm.x1Im.value = (RIm + DIm)/2;
dataForm.x2Re.value = -(term1 + DRe/2) + RRe/2;
dataForm.x2Im.value = (-DIm + RIm)/2;
dataForm.x3Re.value = -(term1 + RRe/2) + ERe/2;
dataForm.x3Im.value = (-RIm + EIm)/2;
dataForm.x4Re.value = -(term1 + (RRe + ERe)/2);
dataForm.x4Im.value = -(RIm + EIm)/2;
return;
}
</script>
</body>
</html>
Your style is very unique compared to other folks I
have read stuff from. Thanks for posting when you have the opportunity, Guess I will
just book mark this page.
Hey there! Someone in my Facebook group shared this site with us so
I came to take a look. I’m definitely enjoying the information. I’m book-marking and
will be tweeting this to my followers! Wonderful blog and superb
design.
It’s great that you are getting thoughts from this paragraph as well
as from our argument made at this time.
I know this web page provides quality depending articles or reviews and other information, is there any other site which gives these kinds of
things in quality?
Hello there, just became aware of your blog through Google, and found that it is
truly informative. I’m gonna watch out for brussels. I’ll be grateful
if you continue this in future. A lot of people will be benefited from your writing.
Cheers!