Conic Sections: Geometric Construction of a Parabola
2016-05-14 18:29
This applet demonstrates the geometric construction and fundamental properties of a parabola within the study of conic sections. Using dynamic geometry tools such as points, segments, midpoints, perpendicular lines, and intersection points, the applet precisely constructs the parabola alongside its key elements: the vertex, the focus, and the directrix. The geometric definition of a parabola — the locus of points equidistant from a fixed point (the focus) and a fixed line (the directrix) — is visually constructed step by step, allowing learners to see how the curve emerges from these elementary geometric objects and relationships.
Users can interactively manipulate the position of the focus and the directrix, observing in real time how the parabola changes shape and orientation in response. This dynamic exploration reinforces the understanding that the vertex lies midway between the focus and the directrix, and that every point on the parabola maintains an equal distance to both. The applet also highlights the axis of symmetry, which passes through the focus and is perpendicular to the directrix, further deepening the learner's grasp of the parabola's structural properties.
The applet is designed for students studying analytic geometry and conic sections. It serves as a visual and interactive supplement to traditional classroom instruction, enabling learners to bridge the gap between abstract algebraic definitions and concrete geometric intuition. By actively engaging with the construction, students develop a deeper, more memorable understanding of why the parabola takes its characteristic shape and how its defining features are interconnected. This hands-on approach supports both discovery-based learning and targeted review, making it a versatile resource for high school and introductory college-level mathematics courses.
Loading the math board and drawing, please wait…
<?xml version="1.0" encoding="utf-8"?>
<geogebra format="5.0" version="5.0.236.0" id="4eeba882-81e3-45a3-b258-16760268b632" xsi:noNamespaceSchemaLocation="http://www.geogebra.org/ggb.xsd" xmlns="" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >
<gui>
<window width="1920" height="1040" />
<perspectives>
<perspective id="tmp">
<panes>
<pane location="" divider="0.10416666666666667" orientation="1" />
</panes>
<views>
<view id="4097" visible="false" inframe="true" stylebar="true" location="1,1,1,1" size="400" window="198,483,700,550" />
<view id="512" toolbar="0 | 1 501 5 19 , 67 | 2 15 45 18 , 7 37 | 514 3 9 , 13 44 , 47 | 16 | 551 550 11 , 20 22 21 23 , 55 56 57 , 12 | 69 | 510 511 , 512 513 | 533 531 , 534 532 , 522 523 , 537 536 , 535 | 521 520 | 36 , 38 49 560 | 571 30 29 570 31 33 | 17 | 540 40 41 42 , 27 28 35 , 6 , 502" visible="false" inframe="false" stylebar="false" location="1,1,1" size="500" window="100,100,600,400" />
<view id="4" toolbar="0 || 2020 , 2021 , 2022 , 66 || 2001 , 2003 , 2002 , 2004 , 2005 || 2040 , 2041 , 2042 , 2044 , 2043" visible="false" inframe="false" stylebar="false" location="1,1" size="300" window="100,100,600,400" />
<view id="8" toolbar="1001 | 1002 | 1003 || 1005 | 1004 || 1006 | 1007 | 1010 || 1008 1009 || 66 68 || 6" visible="false" inframe="false" stylebar="false" location="1,3" size="300" window="100,100,600,400" />
<view id="1" visible="true" inframe="false" stylebar="true" location="1" size="1688" window="100,100,600,400" />
<view id="2" visible="true" inframe="false" stylebar="false" location="3" size="200" window="100,100,250,400" />
<view id="16" visible="false" inframe="false" stylebar="false" location="1" size="150" window="50,50,500,500" />
<view id="32" visible="false" inframe="false" stylebar="true" location="1" size="150" window="50,50,500,500" />
<view id="64" toolbar="0" visible="false" inframe="true" stylebar="true" location="1" size="150" window="50,50,500,500" />
<view id="70" toolbar="0 || 2020 || 2021 || 2022" visible="false" inframe="true" stylebar="true" location="1" size="150" window="50,50,500,500" />
</views>
<toolbar show="true" items="0 39 | 1 501 67 , 5 19 , 72 75 76 | 2 15 45 , 18 65 , 7 37 | 4 3 8 9 , 13 44 , 58 , 47 | 16 51 64 , 70 | 10 34 53 11 , 24 20 22 , 21 23 | 55 56 57 , 12 | 36 46 , 38 49 50 , 71 | 30 29 54 32 31 33 | 17 26 62 73 , 14 68 | 25 52 60 61 | 40 41 42 , 27 28 35 , 6" position="1" help="false" />
<input show="true" cmd="true" top="algebra" />
<dockBar show="true" east="true" />
</perspective>
</perspectives>
<labelingStyle val="0"/>
<font size="12"/>
</gui>
<euclidianView>
<viewNumber viewNo="1"/>
<size width="1688" height="847"/>
<coordSystem xZero="801.5091631153728" yZero="426.8818009210915" scale="85.42710501126795" yscale="85.42710501126804"/>
<evSettings axes="true" grid="true" gridIsBold="false" pointCapturing="3" rightAngleStyle="1" checkboxSize="26" gridType="0"/>
<bgColor r="255" g="255" b="255"/>
<axesColor r="0" g="0" b="0"/>
<gridColor r="192" g="192" b="192"/>
<lineStyle axes="1" grid="0"/>
<axis id="0" show="true" label="" unitLabel="" tickStyle="1" showNumbers="true"/>
<axis id="1" show="true" label="" unitLabel="" tickStyle="1" showNumbers="true"/>
</euclidianView>
<kernel>
<continuous val="false"/>
<usePathAndRegionParameters val="true"/>
<decimals val="2"/>
<angleUnit val="degree"/>
<algebraStyle val="0" spreadsheet="0"/>
<coordStyle val="0"/>
<angleFromInvTrig val="false"/>
</kernel>
<scripting blocked="false" disabled="false"/>
<construction title="" author="" date="">
<element type="point" label="V">
<show object="true" label="false" ev="4"/>
<objColor r="125" g="125" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<animation step="1" speed="1" type="1" playing="false"/>
<coords x="0.0" y="0.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<expression label="h" exp="x(V)" />
<element type="numeric" label="h">
<value val="0.0"/>
<objColor r="0" g="0" b="0" alpha="0.1"/>
</element>
<expression label="k" exp="y(V)" />
<element type="numeric" label="k">
<value val="0.0"/>
<objColor r="0" g="0" b="0" alpha="0.1"/>
</element>
<element type="numeric" label="c">
<value val="1.0"/>
<show object="true" label="true"/>
<objColor r="0" g="0" b="0" alpha="0.1"/>
<layer val="0"/>
<labelMode val="1"/>
<slider min="-5" max="5" absoluteScreenLocation="true" width="400.0" x="30.0" y="50.0" fixed="true" horizontal="true" showAlgebra="true"/>
<lineStyle thickness="10" type="0" typeHidden="1"/>
<animation step="0.1" speed="1" type="0" playing="false"/>
</element>
<expression label="d" exp="(y - k)^(2) = (4 * (c * (x - h)))" type="conic" />
<element type="conic" label="d">
<show object="true" label="false" ev="4"/>
<condition showObject="T_1"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelOffset x="-35" y="72"/>
<labelMode val="1"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<eigenvectors x0="1.0" y0="0.0" z0="1.0" x1="-0.0" y1="1.0" z1="1.0"/>
<matrix A0="0.0" A1="1.0" A2="0.0" A3="0.0" A4="-2.0" A5="0.0"/>
<eqnStyle style="specific"/>
</element>
<expression label="L1" exp="x = h - c" type="line" />
<element type="line" label="L1">
<show object="true" label="false" ev="4"/>
<condition showObject="T_1"/>
<objColor r="255" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="1.0" y="0.0" z="1.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<eqnStyle style="implicit"/>
</element>
<expression label="F" exp="(h + c, k)" type="point" />
<element type="point" label="F">
<show object="true" label="false" ev="4"/>
<condition showObject="T_1"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="1.0" y="0.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<expression label="M1" exp="y = k" type="line" />
<element type="line" label="M1">
<show object="true" label="false" ev="4"/>
<condition showObject="T_1"/>
<objColor r="0" g="0" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="1.0" z="0.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<eqnStyle style="explicit"/>
</element>
<command name="Point">
<input a0="L1"/>
<output a0="C"/>
</command>
<element type="point" label="C">
<show object="false" label="false"/>
<objColor r="125" g="125" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<animation step="1" speed="1" type="1" playing="false"/>
<coords x="-1.0" y="2.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<command name="Point">
<input a0="M1"/>
<output a0="D"/>
</command>
<element type="point" label="D">
<show object="false" label="false"/>
<objColor r="125" g="125" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<animation step="1" speed="1" type="1" playing="false"/>
<coords x="-3.0" y="0.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<expression label="text00" exp=""頂點V=" + (LaTeX[V]) + """ />
<element type="text" label="text00">
<show object="true" label="true" ev="20"/>
<condition showObject="b"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="V"/>
</element>
<expression label="text31" exp=""準線" + (LaTeX[L1]) + """ />
<element type="text" label="text31">
<show object="true" label="true" ev="8"/>
<condition showObject="T_1 ∧ b"/>
<objColor r="255" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="C"/>
</element>
<expression label="text41" exp=""對稱軸" + (LaTeX[M1]) + """ />
<element type="text" label="text41">
<show object="true" label="true" ev="4"/>
<condition showObject="T_1 ∧ b"/>
<objColor r="0" g="0" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="D"/>
</element>
<expression label="text11" exp=""焦點F=" + (LaTeX[F]) + """ />
<element type="text" label="text11">
<show object="true" label="true" ev="20"/>
<condition showObject="T_1 ∧ b"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="F"/>
<labelOffset x="3" y="-44"/>
</element>
<command name="Segment">
<input a0="V" a1="F"/>
<output a0="g1"/>
</command>
<element type="segment" label="g1">
<show object="true" label="false" ev="4"/>
<condition showObject="T_1"/>
<objColor r="255" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="1.0" z="0.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<outlyingIntersections val="false"/>
<keepTypeOnTransform val="true"/>
</element>
<command name="Midpoint">
<input a0="V" a1="F"/>
<output a0="A"/>
</command>
<element type="point" label="A">
<show object="false" label="true"/>
<objColor r="68" g="68" b="68" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.5" y="0.0" z="1.0"/>
<pointSize val="3"/>
<pointStyle val="0"/>
</element>
<expression label="text51" exp=""(y-" + (LaTeX[k]) + ")^2=4×" + (LaTeX[c]) + "(x-" + (LaTeX[h]) + ")"" />
<element type="text" label="text51">
<show object="true" label="true" ev="8"/>
<condition showObject="T_1"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<absoluteScreenLocation x="31" y="98"/>
</element>
<element type="boolean" label="T_1">
<value val="false"/>
<show object="true" label="true"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelOffset x="56" y="178"/>
<labelMode val="0"/>
<checkbox fixed="true"/>
<caption val="橫的"/>
</element>
<expression label="F'" exp="(h, k + c)" type="point" />
<element type="point" label="F'">
<show object="true" label="false" ev="4"/>
<condition showObject="T_2"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="1.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<expression label="M2" exp="x = h" type="line" />
<element type="line" label="M2">
<show object="true" label="false" ev="4"/>
<condition showObject="T_2"/>
<objColor r="0" g="0" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="1.0" y="0.0" z="0.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<eqnStyle style="implicit"/>
</element>
<expression label="L2" exp="y = k - c" type="line" />
<element type="line" label="L2">
<show object="true" label="false" ev="4"/>
<condition showObject="T_2"/>
<objColor r="255" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="1.0" z="1.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<eqnStyle style="explicit"/>
</element>
<expression label="e" exp="(x - h)^(2) = (4 * (c * (y - k)))" type="conic" />
<element type="conic" label="e">
<show object="true" label="false" ev="4"/>
<condition showObject="T_2"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<eigenvectors x0="0.0" y0="1.0" z0="1.0" x1="-1.0" y1="0.0" z1="1.0"/>
<matrix A0="1.0" A1="0.0" A2="0.0" A3="0.0" A4="0.0" A5="-2.0"/>
<eqnStyle style="implicit"/>
</element>
<expression label="text12" exp=""焦點F=" + (LaTeX[F']) + """ />
<element type="text" label="text12">
<show object="true" label="true" ev="20"/>
<condition showObject="T_2 ∧ b"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="F'"/>
</element>
<command name="Midpoint">
<input a0="F'" a1="V"/>
<output a0="A'"/>
</command>
<element type="point" label="A'">
<show object="false" label="true"/>
<objColor r="68" g="68" b="68" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="0.5" z="1.0"/>
<pointSize val="3"/>
<pointStyle val="0"/>
</element>
<expression label="text22" exp=""焦距=" + (LaTeX[c]) + """ />
<element type="text" label="text22">
<show object="true" label="true" ev="20"/>
<condition showObject="T_2 ∧ b"/>
<objColor r="255" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="A'"/>
</element>
<expression label="text21" exp=""焦距=" + (LaTeX[c]) + """ />
<element type="text" label="text21">
<show object="true" label="true" ev="4"/>
<condition showObject="T_1 ∧ b"/>
<objColor r="255" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="A"/>
<labelOffset x="-31" y="-42"/>
</element>
<expression label="text32" exp=""準線" + (LaTeX[L2]) + """ />
<element type="text" label="text32">
<show object="true" label="true" ev="40"/>
<condition showObject="T_2 ∧ b"/>
<objColor r="255" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="E"/>
</element>
<command name="Segment">
<input a0="F'" a1="V"/>
<output a0="g2"/>
</command>
<element type="segment" label="g2">
<show object="true" label="false" ev="4"/>
<condition showObject="T_2"/>
<objColor r="255" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="1.0" y="0.0" z="0.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<outlyingIntersections val="false"/>
<keepTypeOnTransform val="true"/>
</element>
<expression label="text42" exp=""對稱軸" + (LaTeX[M2]) + """ />
<element type="text" label="text42">
<show object="true" label="true" ev="40"/>
<condition showObject="T_2 ∧ b"/>
<objColor r="0" g="0" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="B"/>
</element>
<expression label="text52" exp=""(x-" + (LaTeX[h]) + ")^2=4×" + (LaTeX[c]) + "(y-" + (LaTeX[k]) + ")"" />
<element type="text" label="text52">
<show object="true" label="true" ev="40"/>
<condition showObject="T_2"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<absoluteScreenLocation x="31" y="97"/>
</element>
<command name="Point">
<input a0="M2"/>
<output a0="B"/>
</command>
<element type="point" label="B">
<show object="false" label="true"/>
<objColor r="125" g="125" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<animation step="1" speed="1" type="1" playing="false"/>
<coords x="0.0" y="-2.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<command name="Point">
<input a0="L2"/>
<output a0="E"/>
</command>
<element type="point" label="E">
<show object="false" label="true"/>
<objColor r="125" g="125" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<animation step="1" speed="1" type="1" playing="false"/>
<coords x="2.0" y="-1.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<element type="boolean" label="T_2">
<value val="false"/>
<show object="true" label="true"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelOffset x="142" y="178"/>
<labelMode val="0"/>
<checkbox fixed="true"/>
<caption val="直的"/>
</element>
<element type="boolean" label="b">
<value val="true"/>
<show object="true" label="true"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelOffset x="220" y="176"/>
<labelMode val="0"/>
<checkbox fixed="true"/>
<caption val="標籤"/>
</element>
<command name="Point">
<input a0="d"/>
<output a0="P"/>
</command>
<element type="point" label="P">
<show object="true" label="false" ev="4"/>
<condition showObject="T_1 ∧ (¬b)"/>
<objColor r="125" g="125" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<animation step="0.1" speed="1" type="1" playing="false"/>
<coords x="1.0" y="2.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<expression label="text1" exp=""P""/>
<element type="text" label="text1">
<show object="true" label="true" ev="20"/>
<condition showObject="T_1 ∧ (¬b)"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<fixed val="true"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="P"/>
</element>
<command name="Segment">
<input a0="P" a1="F"/>
<output a0="d1"/>
</command>
<element type="segment" label="d1">
<show object="true" label="false" ev="4"/>
<condition showObject="T_1 ∧ (¬b)"/>
<objColor r="0" g="255" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="2.0" y="0.0" z="-2.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<outlyingIntersections val="false"/>
<keepTypeOnTransform val="true"/>
</element>
<command name="OrthogonalLine">
<input a0="P" a1="L1"/>
<output a0="g"/>
</command>
<element type="line" label="g">
<show object="false" label="true"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="1.0" z="-2.0"/>
<lineStyle thickness="2" type="0" typeHidden="1"/>
<eqnStyle style="implicit"/>
</element>
<command name="Intersect">
<input a0="L1" a1="g"/>
<output a0="G"/>
</command>
<element type="point" label="G">
<show object="false" label="true" ev="4"/>
<objColor r="68" g="68" b="68" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="-1.0" y="2.0" z="1.0"/>
<pointSize val="3"/>
<pointStyle val="0"/>
</element>
<command name="Segment">
<input a0="P" a1="G"/>
<output a0="d2"/>
</command>
<element type="segment" label="d2">
<show object="true" label="false" ev="4"/>
<condition showObject="T_1 ∧ (¬b)"/>
<objColor r="0" g="255" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="-2.0" z="4.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<outlyingIntersections val="false"/>
<keepTypeOnTransform val="true"/>
</element>
<command name="Midpoint">
<input a0="P" a1="F"/>
<output a0="P1"/>
</command>
<element type="point" label="P1">
<show object="false" label="true" ev="4"/>
<objColor r="68" g="68" b="68" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="1.0" y="1.0" z="1.0"/>
<pointSize val="3"/>
<pointStyle val="0"/>
</element>
<command name="Midpoint">
<input a0="P" a1="G"/>
<output a0="P2_1"/>
</command>
<element type="point" label="P2_1">
<show object="false" label="true" ev="4"/>
<objColor r="68" g="68" b="68" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="2.0" z="1.0"/>
<pointSize val="3"/>
<pointStyle val="0"/>
</element>
<expression label="text2" exp=""" + (LaTeX[d1]) + """ />
<element type="text" label="text2">
<show object="true" label="true" ev="20"/>
<condition showObject="T_1 ∧ (¬b)"/>
<objColor r="0" g="255" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="P1"/>
</element>
<expression label="text3" exp=""" + (LaTeX[d2]) + """ />
<element type="text" label="text3">
<show object="true" label="true" ev="20"/>
<condition showObject="T_1 ∧ (¬b)"/>
<objColor r="0" g="255" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="P2_1"/>
</element>
<command name="Point">
<input a0="e"/>
<output a0="P2"/>
</command>
<element type="point" label="P2">
<show object="true" label="false" ev="4"/>
<condition showObject="T_2 ∧ (¬b)"/>
<objColor r="125" g="125" b="255" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<animation step="0.1" speed="1" type="1" playing="false"/>
<coords x="2.0" y="1.0" z="1.0"/>
<pointSize val="5"/>
<pointStyle val="0"/>
</element>
<command name="Segment">
<input a0="P2" a1="F'"/>
<output a0="d3"/>
</command>
<element type="segment" label="d3">
<show object="true" label="false" ev="4"/>
<condition showObject="T_2 ∧ (¬b)"/>
<objColor r="0" g="255" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="0.0" y="-2.0" z="2.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<outlyingIntersections val="false"/>
<keepTypeOnTransform val="true"/>
</element>
<command name="OrthogonalLine">
<input a0="P2" a1="L2"/>
<output a0="i"/>
</command>
<element type="line" label="i">
<show object="false" label="false" ev="4"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="-1.0" y="0.0" z="2.0"/>
<lineStyle thickness="2" type="0" typeHidden="1"/>
<eqnStyle style="implicit"/>
</element>
<command name="Intersect">
<input a0="L2" a1="i"/>
<output a0="H"/>
</command>
<element type="point" label="H">
<show object="false" label="true" ev="4"/>
<objColor r="68" g="68" b="68" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="2.0" y="-1.0" z="1.0"/>
<pointSize val="3"/>
<pointStyle val="0"/>
</element>
<command name="Segment">
<input a0="P2" a1="H"/>
<output a0="d4"/>
</command>
<element type="segment" label="d4">
<show object="true" label="false" ev="4"/>
<condition showObject="T_2 ∧ (¬b)"/>
<objColor r="0" g="255" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="2.0" y="0.0" z="-4.0"/>
<lineStyle thickness="5" type="0" typeHidden="1"/>
<outlyingIntersections val="false"/>
<keepTypeOnTransform val="true"/>
</element>
<command name="Midpoint">
<input a0="P2" a1="F'"/>
<output a0="P3"/>
</command>
<element type="point" label="P3">
<show object="false" label="true" ev="4"/>
<objColor r="68" g="68" b="68" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="1.0" y="1.0" z="1.0"/>
<pointSize val="3"/>
<pointStyle val="0"/>
</element>
<command name="Midpoint">
<input a0="P2" a1="H"/>
<output a0="P4"/>
</command>
<element type="point" label="P4">
<show object="false" label="true" ev="4"/>
<objColor r="68" g="68" b="68" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<coords x="2.0" y="0.0" z="1.0"/>
<pointSize val="3"/>
<pointStyle val="0"/>
</element>
<expression label="text4" exp=""" + (LaTeX[d3]) + """ />
<element type="text" label="text4">
<show object="true" label="true" ev="20"/>
<condition showObject="T_2 ∧ (¬b)"/>
<objColor r="0" g="255" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="P3"/>
</element>
<expression label="text5" exp=""" + (LaTeX[d4]) + """ />
<element type="text" label="text5">
<show object="true" label="true" ev="20"/>
<condition showObject="T_2 ∧ (¬b)"/>
<objColor r="0" g="255" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="P4"/>
</element>
<expression label="text6" exp=""P""/>
<element type="text" label="text6">
<show object="true" label="true" ev="20"/>
<condition showObject="T_2 ∧ (¬b)"/>
<objColor r="0" g="0" b="0" alpha="0.0"/>
<layer val="0"/>
<labelMode val="0"/>
<isLaTeX val="true"/>
<font serif="true" sizeM="2.0" size="12" style="1"/>
<startPoint exp="P2"/>
</element>
</construction>
</geogebra>