使用代数方程库 Algebra.js解二元一次方程

时间：2021-02-18 22:23:41

假设二元一次方程如下：

x + y = 11

x - y = 5

解方程如下：

 <!DOCTYPE html>

 <html lang="zh-CN">

 <head>

     <meta charset="UTF-8" />

     <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />

     <title>测试algebra函数库（解两元一次方程）</title>

     <script src="js/algebra.min.js"></script>

     <script type="text/javascript">

         var Fraction = algebra.Fraction;

         var Expression = algebra.Expression;

         var Equation = algebra.Equation;

         //=======================================

         var x1 = algebra.parse("x+y=11");

         var answer1 = x1.solveFor("y");

         //console.log("y = " + answer1.toString());

         var x2 = algebra.parse("x-y=5");

         var answer2 = x2.solveFor("y");

         //console.log("y = " + answer2.toString());

         //=================================================

         //解出X值

         var eq = new Equation(answer1, answer2);

         console.log("x表达式：" + eq.toString());

         var answerX = eq.solveFor("x");

         console.log("解出X的值为：" + answerX.toString());

         //=================================================

         //解出Y值（把x的值代入x1或x2）

         eq = x1.eval({

             x: answerX

         });

         console.log("y表达式：" + eq.toString());

         var answerY = eq.solveFor("y");

         console.log("解出Y的值为：" + answerY.toString());

     </script>

 </head>

 <body>

 </body>

 </html>

控制台输出：

x表达式：-x + 11 = x - 5

解出X的值为：8

y表达式：y + 8 = 11

解出Y的值为：3

代码写得很粗旷，无任何包装。看得懂就好。

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