Merge pull request #591 from jiggzson/dev

1.1.7

Calculus.js

@@ -655,14 +655,16 @@ if((typeof module) !== 'undefined' && typeof nerdamer === 'undefined') {
                     symbol = _.multiply(polydiff(symbol.clone()), derive(b));  
                 }
                 else if( g === CP || g === PL ) { 
+                    var c = _.parse(symbol);
                     var result = new Symbol(0);
                     for(var x in symbol.symbols) {
                         result = _.add(result, __.diff(symbol.symbols[x].clone(), d));
                     }
-                    symbol = _.multiply(polydiff(symbol.clone()), result);
+                    symbol = _.multiply(polydiff(c), result);
                 }
 
                 symbol.updateHash();
+
                 return symbol;
             };
 
@@ -2586,4 +2588,4 @@ if((typeof module) !== 'undefined' && typeof nerdamer === 'undefined') {
     //link registered functions externally
     nerdamer.api();
 
-})();
+})();

Extra.js

@@ -588,4 +588,4 @@ if ((typeof module) !== 'undefined') {
 
     //link registered functions externally
     nerdamer.api();
-}());
+}());

Solve.js

@@ -66,6 +66,8 @@ if ((typeof module) !== 'undefined') {
     core.Settings.FILTER_SOLUTIONS = true;
     //the maximum number of recursive calls
     core.Settings.MAX_SOLVE_DEPTH = 10;
+    // The tolerance that's considered close enough to zero
+    core.Settings.ZERO_EPSILON = 1e-9;
 
     core.Symbol.prototype.hasTrig = function () {
         return this.containsFunction(['cos', 'sin', 'tan', 'cot', 'csc', 'sec']);
@@ -215,8 +217,7 @@ if ((typeof module) !== 'undefined') {
         else  {
             symbol = this.symbol;
         }
-
-
+
         return solve(symbol, x).map(function (x) {
             return new core.Expression(x);
         });
@@ -1066,7 +1067,10 @@ if ((typeof module) !== 'undefined') {
                 cfact;
 
         var correct_denom = function (symbol) {
-            symbol = _.expand(symbol);
+            symbol = _.expand(symbol, {
+                expand_denominator: true, 
+                expand_functions: true
+            });
             var original = symbol.clone(); //preserve the original
 
             if (symbol.symbols) {
@@ -1180,7 +1184,7 @@ if ((typeof module) !== 'undefined') {
 
         //try for nested sqrts as per issue #486
         add_to_result(__.sqrtSolve(eq, solve_for));
-        
+
         //polynomial single variable
         if (numvars === 1) {
             if (eq.isPoly(true)) {
@@ -1286,7 +1290,6 @@ if ((typeof module) !== 'undefined') {
                     console.log(e);
                 }   
             }
-
         }
         else {
             //The idea here is to go through the equation and collect the coefficients
@@ -1418,13 +1421,33 @@ if ((typeof module) !== 'undefined') {
                 }
             }
         }
-
+        
         if (cfact) {
             solutions = solutions.map(function (x) {
                 return _.pow(x, new Symbol(cfact));
             });
         }
 
+        // Perform some cleanup but don't do it agains arrays, etc
+        // Check it actually evaluates to zero
+        if(isSymbol(eqns)) {
+            var knowns = {};
+            solutions = solutions.filter(function(x) {
+                try {
+                    knowns[solve_for] = x;
+                    var zero = Number(evaluate(eqns, knowns));
+                    // Allow symbolic answers
+                    if(isNaN(zero)) {
+                        return true;
+                    }
+                    return Math.abs(zero) <= core.Settings.ZERO_EPSILON;
+                }
+                catch(e) {
+                    return false;
+                }
+            });
+        }
+
         return solutions;
     };
 
@@ -1471,4 +1494,4 @@ if ((typeof module) !== 'undefined') {
         }
     ]);
     nerdamer.api();
-})();
+})();

index.html

@@ -113,7 +113,7 @@
                 border: 2px solid #ABABAB;
                 border-radius: 3px;
                 padding: 5px;
-                color: 	#707070;
+                color: #707070;
                 font-size: 18px;
                 width: 80%;
                 margin-bottom: 4px;
@@ -131,6 +131,7 @@
                 color: #707070;
                 border-radius: 3px;
                 margin-left: 2px;
+            }
             </style>
         </head>
         <body>