<p>In this article, we study the property of points X on a line <i>l</i> for which the ratio <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12045_2025_1852_Article_IEq1.gif" Format="GIF" Height="23" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(\text{BX}\over \text{CX}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mfrac> <mtext>BX</mtext> <mtext>CX</mtext> </mfrac> </math></EquationSource> </InlineEquation> reaches its maximum and minimum values for two given points B and C. It is known that, in a triangle ABC (AB &gt; AC), the points X on the line <i>l</i>, containing the internal bisector of angle A, where <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12045_2025_1852_Article_IEq1.gif" Format="GIF" Height="23" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(\text{BX}\over \text{CX}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mfrac> <mtext>BX</mtext> <mtext>CX</mtext> </mfrac> </math></EquationSource> </InlineEquation> attains its maximum and minimum values, are the incenter and excenter of the triangle, respectively. While known proofs rely on calculus or trigonometry, we present an elementary geometric solution for the general case of the location of line <i>l</i> relative to segment BC, using the Apollonius circle.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Apollonius Circle in Extremum Problems

  • Victor Oxman

摘要

In this article, we study the property of points X on a line l for which the ratio \(\text{BX}\over \text{CX}\) BX CX reaches its maximum and minimum values for two given points B and C. It is known that, in a triangle ABC (AB > AC), the points X on the line l, containing the internal bisector of angle A, where \(\text{BX}\over \text{CX}\) BX CX attains its maximum and minimum values, are the incenter and excenter of the triangle, respectively. While known proofs rely on calculus or trigonometry, we present an elementary geometric solution for the general case of the location of line l relative to segment BC, using the Apollonius circle.