add exercise on polynomial intuition

Khan · Jan 17, 2012 · 767d7c4 · 767d7c4
1 parent 0415132
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Showing 3 changed files with 256 additions and 126 deletions.
diff --git a/exercises/polynomial_intuition_1.html b/exercises/polynomial_intuition_1.html
@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+<html data-require="math graphie ast math-model">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Polynomial Intuition 1</title>
+    <script src="../khan-exercise.js"></script>
+  </head>
+  <body>
+    <div class="exercise">
+      <div class="problems">
+	<div>
+	  <div class="vars">
+	    <var id="MATH">MathModel.init()</var>
+	    <var id="b">randRangeNonZero(-3, 3)</var>
+	    <var id="A">1</var>
+	    <var id="B">2*b</var>
+	    <var id="C">b*b</var>
+	    <var id="P">MATH.polynomial([A, B, C], "x")</var>
+	    <!-- use parse so that the ast matches the parsed user input -->
+	    <var id="S">MATH.parse("x^2+"+B+"x+"+C)</var>
+	  </div>
+	  <div>
+	    <p class="question">
+	      Write the equation of the following graph:
+	    </p>
+	    <div class="graphie" id="poly">
+	      MATH.graph(P)
+	    </div>
+	  </div>
+	  <div class="solution" data-type="custom"  data-update="poly">
+	    <div class="instruction">
+	      Enter the factored expression here:<br>
+	      <input name="response" type="text" onblur="window._guess=value"></input>
+	    </div>
+	    <div class="guess">window._guess</div>
+	    <div class="validator-function">
+	      var isCorrect = MATH.isEqual(MATH.parse(guess), S);
+	      MATH.graph(MATH.parse(guess), isCorrect?ORANGE:BLUE);
+	      return isCorrect;
+	    </div>
+	    <div class="show-guess">
+	    </div>
+	    <div class="example">x^2-6x+9</div>
+	  </div>
+<!--
+	  <div class="hints">
+	    <p>
+	      Recognize that the expression is of the form
+	      <code><var>MATH.format("a^2+2ab+b^2", "normalsize", KhanUtil.BLUE)</var></code>
+	      , which can be factored as 
+	      <code><var>MATH.format("(a+b)^2", "normalsize", KhanUtil.BLUE)</var></code>.
+	    </p>
+	    <p>
+	      First, determine the values of 
+	      <code><var>MATH.format("a", "normalsize", KhanUtil.BLUE)</var></code> and
+	      <code><var>MATH.format("b", "normalsize", KhanUtil.BLUE)</var></code>.
+	    </p>
+	    <p>
+	      <code><var>MATH.format("a="+"x", "normalsize", KhanUtil.BLUE)</var></code><br><br>
+	      <code><var>MATH.format("b="+2*b+"/"+2+"="+b, "normalsize", KhanUtil.BLUE)</var></code>
+	    </p>
+	    <p>
+	      Replace 
+	      <code><var>MATH.format("a", "normalsize", KhanUtil.BLUE)</var></code> and
+	      <code><var>MATH.format("b", "normalsize", KhanUtil.BLUE)</var></code> in the factored equation to find the answer.
+	    </p>
+	    <p>
+	      <code><var>MATH.format("(x+"+b+")^2", "large", KhanUtil.ORANGE)</var></code>
+	    </p>
+	  </div>
+-->
+	</div>
+      </div>
+    </div>
+  </body>
+</html>
diff --git a/utils/ast.js b/utils/ast.js
@@ -3,7 +3,6 @@
 
    @see http://artcompiler.org/articles/asts-for-khan-exercises.pdf
 
-   var nid = ast.fromExpr(["=", ["+", 1, 1], 2]));
    var node = ast.node(nid);  // returns a node object corresponding to nid
    var expr = ast.node("lhs");
    var answer = ast.node("rhs");
@@ -20,7 +19,7 @@
 jQuery.extend ( KhanUtil, {
 
 
-	ASSERT: false,
+	ASSERT: true,
 
 	assert: function (val, str) {
 		if ( !this.ASSERT ) {