复制代码代码如下:
< html >
< head >
< meta http-equiv="Content-Type" content="text/html" charset="utf-8" >
< title >在线一元二次方程式计算器< /title >
< /head >
< body >
< form name="fquad" >
< p align="center" >解二次方程式计算< br >
< /p >
< table align="center" >
< tbody >
< tr >
< td bgcolor="#990000" >
< h2 >< font color="#ffffff" >< input size="4" name="fa" type="text" > x< sup >2< /sup >+ < input size="4" name="fb" type="text" > x + < input size="4" name="fc" type="text" > = 0 < input onclick="checkQuad()" type="button" value="解题" > < input type="reset" value="重置" > < /font >< /h2 >
< p align="center" >< font color="#ffffff" face="Arial" >< b >一元二次方程的解法< /b >< /font >< /p >
< /td >
< /tr >
< tr >
< td bgcolor="#990000" >
< h2 >< font color="#ffffff" >x< sub >< a style="text-decoration: none" >< font color="#ffffff" >1< /font >< /a >< /sub >=< input size="45" name="x1" type="text" > < br >
x< sub >2< /sub >=< input size="45" name="x2" type="text" > < /font >< /h2 >
< /td >
< /tr >
< tr >
< /tr >
< /tbody >
< /table >
< /form >
< p align="center" >Made by CRoot< /p >
< script language="JavaScript" >
< !--
var rootparti;
var rootpart;
var det;
var rootparti1;
var rootparti2;
var a;
var b;
var c;
var x1;
var x2;
var i = "i";
function checkQuad() {
var a = document.fquad.fa.value;
var b = document.fquad.fb.value;
var c = document.fquad.fc.value;
if (a == 0 && c != 0) {
x1 = -c / b;
x2 = "Not a quadratic equation, but here is your answer for x";
document.fquad.x1.value=x1;
document.fquad.x2.value=x2;
}
else if (a == "" && c != 0) {
x1 = -c / b;
x2 = "Not a quadratic equation";
document.fquad.x1.value=x1;
document.fquad.x2.value=x2;
}
else {
quad();
}
}
function quad() {
var a = document.fquad.fa.value;
var b = document.fquad.fb.value;
var c = document.fquad.fc.value;
det = Math.pow(b,2) - 4 * a * c;
rootpart = Math.sqrt(det) / (2 * a);
rootparti = (Math.sqrt(-det) / (2 * a)) + i;
if (parseFloat(rootparti) < 0) {
rootparti1 = rootparti;
rootparti2 = (-1 * parseFloat(rootparti)) + i;
}
else {
rootparti1 = (-1 * parseFloat(rootparti)) + i;
rootparti2 = rootparti;
}
if (rootparti1 == "1i") {
rootparti1 = i;
rootparti2 = "-i";
}
else if (rootparti1 == "-1i") {
rootparti1 = "-i";
rootparti2 = i;
}
if (det == 0) {
x1 = x2 = -b / (2 * a);
}
else if (det > 0) {
x1 = (-b + Math.sqrt(det)) / (2 * a);
x2 = (-b - Math.sqrt(det)) / (2 * a);
}
else if ((-b / (2 * a)) == 0) {
x1 = rootparti1;
x2 = rootparti2;
}
else {
x1 = (-b / (2 * a) + " + " + rootparti1);
x2 = (-b / (2 * a) + " + " + rootparti2);
}
document.fquad.x1.value=x1;
document.fquad.x2.value=x2;
}
// will solve for complex numbers
// -- >
< /script >
< /body >
< /html >