是否有 JavaScript 库或函数可以求解变量方程？
如
9 = 3 + x我想求婚nerdamer。它可以代数求解四次函数，并且可以数值求解一系列函数。另一个需要考虑的库是 Algebrite。
//solve linear equations
var x = nerdamer.solve('(x+1)*3=x-6', 'x');
console.log(x.toString());
//quadratic
var x2 = nerdamer.solve('x^2-8x+15', 'x');
console.log(x2.toString());
//quadratic algebraically
var x3 = nerdamer.solve('x^2-ax+3*b', 'x');
console.log(x3.toString());
//multiple roots
var x4 = nerdamer.solve('x^6+41*x^5+652*x^4+5102*x^3+20581*x^2+40361*x+30030', 'x');
console.log(x4.toString());
//functions - numerically around to zero up to a predefined range
var x5 = nerdamer.solve('cos(x)^2+sin(x-1)', 'x');
console.log(x5.toString());
//solve a system of linear equations
var x6 = nerdamer.solveEquations(['2x+y=7', 'x-y+3z=11', 'y-z=-1']);
console.log(x6.toString());
//solve a system of nonlinear equations
var x7 = nerdamer.solveEquations(['3*x^2/y=2', 'z*x*y-1=35', '5*z^2+7=52']);
console.log(x7.toString());<script src="https://cdn.jsdelivr.net/npm/nerdamer@latest/nerdamer.core.js"></script>
<script src="https://cdn.jsdelivr.net/npm/nerdamer@latest/Algebra.js"></script>
<script src="https://cdn.jsdelivr.net/npm/nerdamer@latest/Calculus.js"></script>
<script src="https://cdn.jsdelivr.net/npm/nerdamer@latest/Solve.js"></script>您可以通过执行 excel 所谓的“目标寻求”来近似解决方案 - 测试
x"="xeval对于一个像人类一样实际求解方程的程序（通过重新排列方程的两侧并应用反函数、导数/积分等等）要复杂得多，并且在某种程度上感觉完全是专有的；）
快速搜索会发现 algebra.js 和 js-solver。我对他们一无所知，但他们看起来很合法。 algebra.js 有一个很好的 OOP API，但似乎无法处理三角函数。
查看牛顿方法程序中的脚本，其中 f(x)=0。它使用牛顿正切法求解方程。
Ceres.js 可以找到 f(x) = 0 形式的方程组的解。它是通过 Emscripten 从 C++ 移植到 JavaScript 的。该文件有点大，但如果您需要真正高性能的求解器，这是您最好的选择。它以网络组装方式运行，因此速度很高。 这是一个例子：
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
</head>
<body>
<h3>Powell Function</h3>
<p>This is an example of the solution of the powell function using Ceres.js</p>
<pre><code id="powell_demo_code" class="language-js"></code></pre>
<textarea id="powell_demo" rows="40" cols="110"></textarea>
<script id="powell_demo_code_source">
async function ceresSolvePowell() {
const {Ceres} = await import('https://cdn.jsdelivr.net/gh/Pterodactylus/Ceres.js@latest/dist/ceres.min.js');
var fn1 = function f1(x){
return (x[0]+10*x[1]);
}
var fn2 = function f2(x){
return (Math.sqrt(5)*(x[2]-x[3]));
}
var fn3 = function f3(x){
return Math.pow(x[1]-2*x[2],2);
}
var fn4 = function f4(x){
return Math.sqrt(10)*Math.pow(x[0]-x[3],2);
}
let solver = new Ceres()
solver.addFunction(fn1) //Add the first equation to the solver.
solver.addFunction(fn2) //Add the second equation to the solver.
solver.addFunction(fn3) //Add the third equation to the solver.
solver.addFunction(fn4) //Add the forth equation to the solver.
//solver.addCallback(c1) //Add the callback to the solver.
//solver.addLowerbound(0,1.6) //Add a lower bound to the x[0] variable
//solver.addUpperbound(1,1.7) //Add a upper bound to the x[1] variable
var x_guess = [1,2,3,4] //Guess the initial values of the solution.
let s = await solver.solve(x_guess) //Solve the equation
var x = s.x //assign the calculated solution array to the variable x
document.getElementById("powell_demo").value = s.report //Print solver report
solver.remove() //required to free the memory in C++
}
ceresSolvePowell();
</script>
</body>
</html>