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  <title>Conic Concepts -- Introduction</title>
  <metadata xmlns:md="http://cnx.rice.edu/mdml" mdml-version="0.5">
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  <md:content-url>http://cnx.org/content/m18265/latest/</md:content-url>
  <md:content-id>m18265</md:content-id>
  <md:title>Conic Concepts -- Introduction</md:title>
  <md:version>1.2</md:version>
  <md:created>2008/10/07 11:13:58 GMT-5</md:created>
  <md:revised>2010/03/22 14:19:34.287 GMT-5</md:revised>
  <md:actors>
    <md:person userid="kennyfelder">
      <md:firstname>Kenny</md:firstname>
      <md:surname>Felder</md:surname>
      <md:fullname>Kenny M. Felder</md:fullname>
      <md:email>KFelder@RaleighCharterHS.org</md:email>
    </md:person>
  </md:actors>
  <md:roles>
    <md:role type="author">kennyfelder</md:role>
    <md:role type="maintainer">kennyfelder</md:role>
    <md:role type="licensor">kennyfelder</md:role>
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  <md:license url="http://creativecommons.org/licenses/by/2.0/"/>
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  <md:keywordlist>
    <md:keyword>algebra</md:keyword>
    <md:keyword>conic sections</md:keyword>
    <md:keyword>graphing</md:keyword>
  </md:keywordlist>
  <md:subjectlist>
    <md:subject>Mathematics and Statistics</md:subject>
  </md:subjectlist>
  <md:abstract>This module introduces the concept of conic sections in Algebra.</md:abstract>
  <md:language>en</md:language>
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    <link-group type="supplemental">
      <link url="http://www.brightstorm.com/d/math/s/algebra-2/u/conic-sections/t/conic-section-formulas" strength="3">Conic Section Formulas Video</link>
      <link url="http://www.brightstorm.com/d/math/s/algebra-2/u/conic-sections/t/introduction-to-conic-sections" strength="3">Conic Sections Video</link>
    </link-group>
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</featured-links>
<content>


      <para id="id3612924">So far, we have talked about how to graph two shapes: lines, and parabolas. This unit will discuss parabolas in more depth. It will also discuss circles, ellipses, and hyperbolas. These shapes make up the group called the <emphasis>conic sections</emphasis>: all the shapes that can be created by intersecting a <emphasis>plane</emphasis> with a <emphasis>double cone</emphasis>.</para>
      <table id="id3352306" summary="">
<tgroup cols="3"><colspec colnum="1" colname="c1"/>
          <colspec colnum="2" colname="c2"/>
          <colspec colnum="3" colname="c3"/>
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            <row>
              <entry>
      <media id="id4636106" alt="A picture of two cones connected at the tips."><image src="cnc1.PNG" mime-type="image/png" print-width="3in"/></media>
      </entry>
              <entry>On the left is a <emphasis>double cone.</emphasis>If you intersect the double cone with a horizontal plane, you get a <emphasis>circle.</emphasis>If you tilt the plane a bit, you get an <emphasis>ellipse</emphasis> (as in the bad clip art picture on the right).If you tilt the plane more, so it never hits the other side of the cone, you get a <emphasis>parabola.</emphasis>If the plane is vertical, so it hits both cones, you get a <emphasis>hyperbola.</emphasis></entry>
              <entry>
            <media id="id41644234" alt="A picture of a cone intersected with a plane."><image src="cnc2.PNG" mime-type="image/png" print-width="3in"/></media>
      </entry>
            </row>
          </tbody>
        


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      <para id="id3663229">We are going to discuss each of these shapes in some detail. Specifically, for each shape, we are going to provide...</para>
      <list id="id3489301" list-type="bulleted">
        <item>A formal <emphasis>definition</emphasis> of the shape, and</item>
        <item>The <emphasis>formula</emphasis> for graphing the shape</item>
      </list>
      <para id="id3416705">These two things—the definition, and the formula—may in many cases seem unrelated. But you will be doing work in the text exercises to show, for each shape, how the definition <emphasis>leads to</emphasis> the formula.</para>


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