JavaScript 中的二次方程求解器
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时间：2020-10-28 16:30:35 来源:igfitidea点击:
Quadratic Equation Solver in JavaScript
提问by Stardust
For some reason, when a=1, b=1, c=-1, I am not getting the desired result of -1.6180339887499 and 0.61803398874989. Instead, I get 2 and 1. What am I doing wrong?
出于某种原因，当 a=1、b=1、c=-1 时，我没有得到 -1.6180339887499 和 0.61803398874989 的预期结果。相反，我得到 2 和 1。我做错了什么？
function solve(a,b,c){
var result = (((-1*b) + Math.sqrt(Math.pow(b,2)) - (4*a*c))/(2*a));
var result2 = (((-1*b) - Math.sqrt(Math.pow(b,2)) - (4*a*c))/(2*a));
return result + "<br>" + result2;
}
document.write( solve(1,1,-1) );回答by Nina Scholz
You need another grouping:
您需要另一个分组：
var result = (((-1 * b) + Math.sqrt(Math.pow(b, 2)) - (4 * a * c)) / (2 * a)); // wrong
var result2 = (((-1 * b) - Math.sqrt(Math.pow(b, 2)) - (4 * a * c)) / (2 * a)); // wrong
vs
对比
var result = (-1 * b + Math.sqrt(Math.pow(b, 2) - (4 * a * c))) / (2 * a); // right
var result2 = (-1 * b - Math.sqrt(Math.pow(b, 2) - (4 * a * c))) / (2 * a); // right
All together:
全部一起：
function solve(a, b, c) {
var result = (-1 * b + Math.sqrt(Math.pow(b, 2) - (4 * a * c))) / (2 * a);
var result2 = (-1 * b - Math.sqrt(Math.pow(b, 2) - (4 * a * c))) / (2 * a);
return result + "<br>" + result2;
}
document.write(solve(1, 1, -1));回答by Hari Mohan
Try
尝试
var a, b, c, discriminant, root1, root2, r_Part, imag_Part;
document.write(realpart ="+r_Part" and imaganary part ="+imag_Part");
discriminant = b*b-4*a*c;
if (discriminant > 0)
{
root1 = (-b+sqrt(discriminant))/(2*a);
root2 = (-b-sqrt(discriminant))/(2*a);
document.write(real part ="+r_Part" and imaganary part ="+imag_Part");
}
else if (discriminant == 0)
{
root1 = root2 = -b/(2*a);
document.write(real part ="+r_Part" and imaganary part ="+imag_Part");
}
else
{
r_Part = -b/(2*a);
imag_Part = sqrt(-discriminant)/(2*a);
document.write(real part ="+r_Part" and imaganary part ="+imag_Part");
}
回答by kranthi goud
function solve(a, b, c) {
var result = ((-1 * b + Math.sqrt(Math.pow(b, 2) - (4 * a * c))) / (2 * a)).toFixed(3);
var result2 = (-1 * b - Math.sqrt(Math.pow(b, 2) - (4 * a * c))) / (2 * a).toFixed(3);
return "{"+result + "," + result2+"}";
}
document.write(solve(1, -4, -7));
