Curves Related to the Gergonne Point in an Isotropic Plane

The notion of the Gergonne point of a triangle in the Euclidean plane is very well known, and the study of them in the isotropic setting has already appeared earlier. In this paper, we give two generalizations of the Gergonne point of a triangle in the isotropic plane, and we study several curves re...

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Main Authors: Ema Jurkin, Marija Šimić Horvath
Format: Article
Language:English
Published: MDPI AG 2023-03-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/11/7/1562
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author Ema Jurkin
Marija Šimić Horvath
author_facet Ema Jurkin
Marija Šimić Horvath
author_sort Ema Jurkin
collection DOAJ
description The notion of the Gergonne point of a triangle in the Euclidean plane is very well known, and the study of them in the isotropic setting has already appeared earlier. In this paper, we give two generalizations of the Gergonne point of a triangle in the isotropic plane, and we study several curves related to them. The first generalization is based on the fact that for the triangle <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><mi>B</mi><mi>C</mi></mrow></semantics></math></inline-formula> and its contact triangle <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>A</mi><mi>i</mi></msub><msub><mi>B</mi><mi>i</mi></msub><msub><mi>C</mi><mi>i</mi></msub></mrow></semantics></math></inline-formula>, there is a pencil of circles such that each circle <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>k</mi><mi>m</mi></msub></semantics></math></inline-formula> from the pencil the lines <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><msub><mi>A</mi><mi>m</mi></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>B</mi><msub><mi>B</mi><mi>m</mi></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>C</mi><msub><mi>C</mi><mi>m</mi></msub></mrow></semantics></math></inline-formula> is concurrent at a point <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>G</mi><mi>m</mi></msub></semantics></math></inline-formula>, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>A</mi><mi>m</mi></msub></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>B</mi><mi>m</mi></msub></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>C</mi><mi>m</mi></msub></semantics></math></inline-formula> are points on <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>k</mi><mi>m</mi></msub></semantics></math></inline-formula> parallel to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>A</mi><mi>i</mi></msub><mo>,</mo><msub><mi>B</mi><mi>i</mi></msub><mo>,</mo><msub><mi>C</mi><mi>i</mi></msub></mrow></semantics></math></inline-formula>, respectively. To introduce the second generalization of the Gergonne point, we prove that for the triangle <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><mi>B</mi><mi>C</mi></mrow></semantics></math></inline-formula>, point <i>I</i> and three lines <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>q</mi><mn>1</mn></msub><mo>,</mo><msub><mi>q</mi><mn>2</mn></msub><mo>,</mo><msub><mi>q</mi><mn>3</mn></msub></mrow></semantics></math></inline-formula> through <i>I</i> there are two points <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>G</mi><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></semantics></math></inline-formula> such that for the points <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>Q</mi><mn>1</mn></msub><mo>,</mo><msub><mi>Q</mi><mn>2</mn></msub><mo>,</mo><msub><mi>Q</mi><mn>3</mn></msub></mrow></semantics></math></inline-formula> on <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>q</mi><mn>1</mn></msub><mo>,</mo><msub><mi>q</mi><mn>2</mn></msub><mo>,</mo><msub><mi>q</mi><mn>3</mn></msub></mrow></semantics></math></inline-formula> with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>d</mi><mrow><mo>(</mo><mi>I</mi><mo>,</mo><msub><mi>Q</mi><mn>1</mn></msub><mo>)</mo></mrow><mo>=</mo><mi>d</mi><mrow><mo>(</mo><mi>I</mi><mo>,</mo><msub><mi>Q</mi><mn>2</mn></msub><mo>)</mo></mrow><mo>=</mo><mi>d</mi><mrow><mo>(</mo><mi>I</mi><mo>,</mo><msub><mi>Q</mi><mn>3</mn></msub><mo>)</mo></mrow></mrow></semantics></math></inline-formula>, the lines <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><msub><mi>Q</mi><mn>1</mn></msub><mo>,</mo><mi>B</mi><msub><mi>Q</mi><mn>2</mn></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>C</mi><msub><mi>Q</mi><mn>3</mn></msub></mrow></semantics></math></inline-formula> are concurrent at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>G</mi><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></semantics></math></inline-formula>. We achieve these results by using the standardization of the triangle in the isotropic plane and simple analytical method.
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spelling doaj.art-c591ff86dd064ac7910eb1c2ec03d3d82023-11-17T17:07:23ZengMDPI AGMathematics2227-73902023-03-01117156210.3390/math11071562Curves Related to the Gergonne Point in an Isotropic PlaneEma Jurkin0Marija Šimić Horvath1Faculty of Mining, Geology and Petroleum Engineering, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, CroatiaFaculty of Architecture, University of Zagreb, Kačićeva 26, HR-10000 Zagreb, CroatiaThe notion of the Gergonne point of a triangle in the Euclidean plane is very well known, and the study of them in the isotropic setting has already appeared earlier. In this paper, we give two generalizations of the Gergonne point of a triangle in the isotropic plane, and we study several curves related to them. The first generalization is based on the fact that for the triangle <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><mi>B</mi><mi>C</mi></mrow></semantics></math></inline-formula> and its contact triangle <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>A</mi><mi>i</mi></msub><msub><mi>B</mi><mi>i</mi></msub><msub><mi>C</mi><mi>i</mi></msub></mrow></semantics></math></inline-formula>, there is a pencil of circles such that each circle <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>k</mi><mi>m</mi></msub></semantics></math></inline-formula> from the pencil the lines <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><msub><mi>A</mi><mi>m</mi></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>B</mi><msub><mi>B</mi><mi>m</mi></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>C</mi><msub><mi>C</mi><mi>m</mi></msub></mrow></semantics></math></inline-formula> is concurrent at a point <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>G</mi><mi>m</mi></msub></semantics></math></inline-formula>, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>A</mi><mi>m</mi></msub></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>B</mi><mi>m</mi></msub></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>C</mi><mi>m</mi></msub></semantics></math></inline-formula> are points on <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>k</mi><mi>m</mi></msub></semantics></math></inline-formula> parallel to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>A</mi><mi>i</mi></msub><mo>,</mo><msub><mi>B</mi><mi>i</mi></msub><mo>,</mo><msub><mi>C</mi><mi>i</mi></msub></mrow></semantics></math></inline-formula>, respectively. To introduce the second generalization of the Gergonne point, we prove that for the triangle <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><mi>B</mi><mi>C</mi></mrow></semantics></math></inline-formula>, point <i>I</i> and three lines <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>q</mi><mn>1</mn></msub><mo>,</mo><msub><mi>q</mi><mn>2</mn></msub><mo>,</mo><msub><mi>q</mi><mn>3</mn></msub></mrow></semantics></math></inline-formula> through <i>I</i> there are two points <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>G</mi><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></semantics></math></inline-formula> such that for the points <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>Q</mi><mn>1</mn></msub><mo>,</mo><msub><mi>Q</mi><mn>2</mn></msub><mo>,</mo><msub><mi>Q</mi><mn>3</mn></msub></mrow></semantics></math></inline-formula> on <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>q</mi><mn>1</mn></msub><mo>,</mo><msub><mi>q</mi><mn>2</mn></msub><mo>,</mo><msub><mi>q</mi><mn>3</mn></msub></mrow></semantics></math></inline-formula> with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>d</mi><mrow><mo>(</mo><mi>I</mi><mo>,</mo><msub><mi>Q</mi><mn>1</mn></msub><mo>)</mo></mrow><mo>=</mo><mi>d</mi><mrow><mo>(</mo><mi>I</mi><mo>,</mo><msub><mi>Q</mi><mn>2</mn></msub><mo>)</mo></mrow><mo>=</mo><mi>d</mi><mrow><mo>(</mo><mi>I</mi><mo>,</mo><msub><mi>Q</mi><mn>3</mn></msub><mo>)</mo></mrow></mrow></semantics></math></inline-formula>, the lines <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>A</mi><msub><mi>Q</mi><mn>1</mn></msub><mo>,</mo><mi>B</mi><msub><mi>Q</mi><mn>2</mn></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>C</mi><msub><mi>Q</mi><mn>3</mn></msub></mrow></semantics></math></inline-formula> are concurrent at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>G</mi><mrow><mn>1</mn><mo>,</mo><mn>2</mn></mrow></msub></semantics></math></inline-formula>. We achieve these results by using the standardization of the triangle in the isotropic plane and simple analytical method.https://www.mdpi.com/2227-7390/11/7/1562isotropic planeGergonne pointgeneralized Gergonne points
spellingShingle Ema Jurkin
Marija Šimić Horvath
Curves Related to the Gergonne Point in an Isotropic Plane
Mathematics
isotropic plane
Gergonne point
generalized Gergonne points
title Curves Related to the Gergonne Point in an Isotropic Plane
title_full Curves Related to the Gergonne Point in an Isotropic Plane
title_fullStr Curves Related to the Gergonne Point in an Isotropic Plane
title_full_unstemmed Curves Related to the Gergonne Point in an Isotropic Plane
title_short Curves Related to the Gergonne Point in an Isotropic Plane
title_sort curves related to the gergonne point in an isotropic plane
topic isotropic plane
Gergonne point
generalized Gergonne points
url https://www.mdpi.com/2227-7390/11/7/1562
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