tweaks

components/sections/abc/index.js

@@ -187,7 +187,7 @@ var ABC = React.createClass({
           with quadratic or cubic curves:</p>
 
           <p>\[\begin{align}
-            & u(t)_{quadratic} = \frac{(t-1)^2}{2t^2 - 2t + 1} \\
+            & u(t)_{quadratic} = \frac{(1-t)^2}{t^2 + (1-t)^2} \\
             & u(t)_{cubic} = \frac{(1-t)^3}{t^3 + (1-t)^3}
           \end{align}\]</p>
 
@@ -228,7 +228,7 @@ var ABC = React.createClass({
           while the "u(t)" functions have the same name both here and on MathOverflow.</p>
 
           <p>\[
-            ratio(t)_{quadratic} = \left | \frac{2t^2 - 2t}{2t^2 - 2t + 1} \right |
+            ratio(t)_{quadratic} = \left | \frac{t^2 + (1-t)^2 - 1}{t^2 + (1-t)^2} \right |
           \]</p>
 
           <p>\[

components/sections/circles/index.js

@@ -187,14 +187,14 @@ var Circles = React.createClass({
         number of ranges for the angle φ, such as a half circle, quarter circle and eighth circle?</p>
 
         <table><tbody><tr><td>
-          <p><img src="images/arc-q-pi.gif"/></p>
+          <p><img src="images/arc-q-pi.gif" height="190px"/></p>
           <p>plotted for 0 ≤ φ ≤ π:</p>
         </td><td>
-          <p><img src="images/arc-q-pi2.gif"/></p>
+          <p><img src="images/arc-q-pi2.gif" height="187px"/></p>
           <p>plotted for 0 ≤ φ ≤ ½π:</p>
         </td><td>
           { this.props.showhref ? "http://www.wolframalpha.com/input/?i=plot+sqrt%28%281%2F4+*+%28sin%28x%29+%2B+2tan%28x%2F2%29%29+-+sin%28x%2F2%29%29%5E2+%2B+%282sin%5E4%28x%2F4%29%29%5E2%29+for+0+%3C%3D+x+%3C%3D+pi%2F4" : null }
-          <p><img src="images/arc-q-pi4.gif"/></p>
+          <p><img src="images/arc-q-pi4.gif" height="174px"/></p>
           <p>plotted for 0 ≤ φ ≤ ¼π:</p>
         </td></tr></tbody></table>
 

components/sections/circles_cubic/index.js

@@ -263,13 +263,13 @@ var CirclesCubic = React.createClass({
         and see what the error is for circular arcs with an angle ranging from 0 to 2π:</p>
 
         <table><tbody><tr><td>
-          <p><img src="images/arc-c-2pi.gif"/></p>
+          <p><img src="images/arc-c-2pi.gif" height="187px"/></p>
           <p>plotted for 0 ≤ φ ≤ 2π:</p>
         </td><td>
-          <p><img src="images/arc-c-pi.gif"/></p>
+          <p><img src="images/arc-c-pi.gif" height="187px"/></p>
           <p>plotted for 0 ≤ φ ≤ π:</p>
         </td><td>
-          <p><img src="images/arc-c-pi2.gif"/></p>
+          <p><img src="images/arc-c-pi2.gif" height="187px"/></p>
           <p>plotted for 0 ≤ φ ≤ ½π:</p>
         </td></tr></tbody></table>
 

components/sections/comments/index.js

@@ -0,0 +1,34 @@
+var React = require("react");
+
+var style = {
+  width: 'calc(960px + 2em)',
+  marginTop: 0,
+  borderTop: '1px solid rgba(255, 0, 0, 0.5)',
+  paddingTop: '3em'
+};
+
+var sectionHTML = (
+  <section id="comments" style={style}>
+    <h2>Comments and questions</h2>
+    <div id="disqus_thread"/>
+  </section>
+);
+
+var CommentsAndQuestions = React.createClass({
+  getDefaultProps: function() {
+    return {
+      title: "Comments and Questions"
+    };
+  },
+  componentDidMount: function() {
+    if (typeof document !== "undefined") {
+      var disqusScript = document.createElement("script");
+      disqusScript.setAttribute("async", "async");
+      disqusScript.src = "lib/site/disqus.js";
+      document.head.appendChild(disqusScript);
+    }
+  },
+  render: function() { return sectionHTML; }
+});
+
+module.exports = CommentsAndQuestions;

components/sections/extended/index.js

@@ -87,8 +87,8 @@ var Explanation = React.createClass({
         more "shape" hidden in the rest of the curve, and we can model those parts by moving the curve
         points around.</p>
 
-        <Graphic preset="simple" title="Quadratic infinite internval Bézier curve" setup={this.setupQuadratic} draw={this.draw} />
-        <Graphic preset="simple" title="Cubic infinite internval Bézier curve" setup={this.setupCubic} draw={this.draw} />
+        <Graphic preset="simple" title="Quadratic infinite interval Bézier curve" setup={this.setupQuadratic} draw={this.draw} />
+        <Graphic preset="simple" title="Cubic infinite interval Bézier curve" setup={this.setupCubic} draw={this.draw} />
 
         <p>In fact, there are curves used in graphics design and computer modelling that do the opposite
         of Bézier curves, where rather than fixing the interval, and giving you free coordinates, they fix

components/sections/index.js

@@ -50,5 +50,7 @@ module.exports = {
 
   circles: require("./circles"),
   circles_cubic: require("./circles_cubic"),
-  arcapproximation: require("./arcapproximation")
+  arcapproximation: require("./arcapproximation"),
+
+  comments: require("./comments")
 };