代码如下:
在线一元二次方程式计算器Made by CRoot
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
// -->
