Historical Introduction to Geometry
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Models of 2-Dimensional Hyperbolic Space and Relations Among Them; Hyperbolic Length, Lines, and Distances
Models of 2-dimensional hyperbolic space and relations among them; Hyperbolic length, lines, and distances Cheng Ka Long, Hui Kam Tong 1155109623, 1155109049 Course Teacher: Prof. Yi-Jen LEE Department of Mathematics, The Chinese University of Hong Kong MATH4900E Presentation 2, 5th October 2020 Outline Upper half-plane Model (Cheng) A Model for the Hyperbolic Plane The Riemann Sphere C Poincar´eDisc Model D (Hui) Basic properties of Poincar´eDisc Model Relation between D and other models Length and distance in the upper half-plane model (Cheng) Path integrals Distance in hyperbolic geometry Measurements in the Poincar´eDisc Model (Hui) M¨obiustransformations of D Hyperbolic length and distance in D Conclusion Boundary, Length, Orientation-preserving isometries, Geodesics and Angles Reference Upper half-plane model H Introduction to Upper half-plane model - continued Hyperbolic geometry Five Postulates of Hyperbolic geometry: 1. A straight line segment can be drawn joining any two points. 2. Any straight line segment can be extended indefinitely in a straight line. 3. A circle may be described with any given point as its center and any distance as its radius. 4. All right angles are congruent. 5. For any given line R and point P not on R, in the plane containing both line R and point P there are at least two distinct lines through P that do not intersect R. Some interesting facts about hyperbolic geometry 1. Rectangles don't exist in hyperbolic geometry. 2. In hyperbolic geometry, all triangles have angle sum < π 3. In hyperbolic geometry if two triangles are similar, they are congruent. -
Geometry Around Us an Introduction to Non-Euclidean Geometry
Geometry Around Us An Introduction to Non-Euclidean Geometry Gaurish Korpal (gaurish4math.wordpress.com) National Institute of Science Education and Research, Bhubaneswar 23 April 2016 Science Day Celebration Gaurish Korpal(gaurish4math.wordpress.com) (NISER) Geometry Around Us 23 April 2016 1 / 15 Theorem In any triangle, trisector lines intersect at three points, that are vertices of an equilateral triangle. A. Bogomolny, Morley's Theorem: Proof by R. J. Webster, Interactive Mathematics Miscellany and Puzzle, http://www.cut-the-knot.org/triangle/Morley/Webster.shtml Morley's Miracle Frank Morley (USA) discovered a theorem about triangle in 1899, approximately 2000 years after first theorems about triangle were published by Euclid. Euclid (Egypt) is referred as father of Plane Geometry, often called Euclidean Geometry. Science Day Celebration Gaurish Korpal(gaurish4math.wordpress.com) (NISER) Geometry Around Us 23 April 2016 2 / 15 Morley's Miracle Frank Morley (USA) discovered a theorem about triangle in 1899, approximately 2000 years after first theorems about triangle were published by Euclid. Euclid (Egypt) is referred as father of Plane Geometry, often called Euclidean Geometry. Theorem In any triangle, trisector lines intersect at three points, that are vertices of an equilateral triangle. A. Bogomolny, Morley's Theorem: Proof by R. J. Webster, Interactive Mathematics Miscellany and Puzzle, http://www.cut-the-knot.org/triangle/Morley/Webster.shtml Science Day Celebration Gaurish Korpal(gaurish4math.wordpress.com) (NISER) Geometry Around Us 23 April 2016 2 / 15 Morley's original proof was (published in 1924) stemmed from his results on algebraic curves tangent to a given number of lines. It arose from the consideration of cardioids [(x 2 + y 2 − a2)2 = 4a2((x − a)2 + y 2)]. -
Analytic Geometry
STATISTIC ANALYTIC GEOMETRY SESSION 3 STATISTIC SESSION 3 Session 3 Analytic Geometry Geometry is all about shapes and their properties. If you like playing with objects, or like drawing, then geometry is for you! Geometry can be divided into: Plane Geometry is about flat shapes like lines, circles and triangles ... shapes that can be drawn on a piece of paper Solid Geometry is about three dimensional objects like cubes, prisms, cylinders and spheres Point, Line, Plane and Solid A Point has no dimensions, only position A Line is one-dimensional A Plane is two dimensional (2D) A Solid is three-dimensional (3D) Plane Geometry Plane Geometry is all about shapes on a flat surface (like on an endless piece of paper). 2D Shapes Activity: Sorting Shapes Triangles Right Angled Triangles Interactive Triangles Quadrilaterals (Rhombus, Parallelogram, etc) Rectangle, Rhombus, Square, Parallelogram, Trapezoid and Kite Interactive Quadrilaterals Shapes Freeplay Perimeter Area Area of Plane Shapes Area Calculation Tool Area of Polygon by Drawing Activity: Garden Area General Drawing Tool Polygons A Polygon is a 2-dimensional shape made of straight lines. Triangles and Rectangles are polygons. Here are some more: Pentagon Pentagra m Hexagon Properties of Regular Polygons Diagonals of Polygons Interactive Polygons The Circle Circle Pi Circle Sector and Segment Circle Area by Sectors Annulus Activity: Dropping a Coin onto a Grid Circle Theorems (Advanced Topic) Symbols There are many special symbols used in Geometry. Here is a short reference for you: -
Constructive Solid Geometry Concepts
3-1 Chapter 3 Constructive Solid Geometry Concepts Understand Constructive Solid Geometry Concepts Create a Binary Tree Understand the Basic Boolean Operations Use the SOLIDWORKS CommandManager User Interface Setup GRID and SNAP Intervals Understand the Importance of Order of Features Use the Different Extrusion Options 3-2 Parametric Modeling with SOLIDWORKS Certified SOLIDWORKS Associate Exam Objectives Coverage Sketch Entities – Lines, Rectangles, Circles, Arcs, Ellipses, Centerlines Objectives: Creating Sketch Entities. Rectangle Command ................................................3-10 Boss and Cut Features – Extrudes, Revolves, Sweeps, Lofts Objectives: Creating Basic Swept Features. Base Feature .............................................................3-9 Reverse Direction Option ........................................3-16 Hole Wizard ..............................................................3-20 Dimensions Objectives: Applying and Editing Smart Dimensions. Reposition Smart Dimension ..................................3-11 Feature Conditions – Start and End Objectives: Controlling Feature Start and End Conditions. Reference Guide Reference Extruded Cut, Up to Next .......................................3-25 Associate Certified Constructive Solid Geometry Concepts 3-3 Introduction In the 1980s, one of the main advancements in solid modeling was the development of the Constructive Solid Geometry (CSG) method. CSG describes the solid model as combinations of basic three-dimensional shapes (primitive solids). The -
A Historical Introduction to Elementary Geometry
i MATH 119 – Fall 2012: A HISTORICAL INTRODUCTION TO ELEMENTARY GEOMETRY Geometry is an word derived from ancient Greek meaning “earth measure” ( ge = earth or land ) + ( metria = measure ) . Euclid wrote the Elements of geometry between 330 and 320 B.C. It was a compilation of the major theorems on plane and solid geometry presented in an axiomatic style. Near the beginning of the first of the thirteen books of the Elements, Euclid enumerated five fundamental assumptions called postulates or axioms which he used to prove many related propositions or theorems on the geometry of two and three dimensions. POSTULATE 1. Any two points can be joined by a straight line. POSTULATE 2. Any straight line segment can be extended indefinitely in a straight line. POSTULATE 3. Given any straight line segment, a circle can be drawn having the segment as radius and one endpoint as center. POSTULATE 4. All right angles are congruent. POSTULATE 5. (Parallel postulate) If two lines intersect a third in such a way that the sum of the inner angles on one side is less than two right angles, then the two lines inevitably must intersect each other on that side if extended far enough. The circle described in postulate 3 is tacitly unique. Postulates 3 and 5 hold only for plane geometry; in three dimensions, postulate 3 defines a sphere. Postulate 5 leads to the same geometry as the following statement, known as Playfair's axiom, which also holds only in the plane: Through a point not on a given straight line, one and only one line can be drawn that never meets the given line. -
Geometry Course Outline
GEOMETRY COURSE OUTLINE Content Area Formative Assessment # of Lessons Days G0 INTRO AND CONSTRUCTION 12 G-CO Congruence 12, 13 G1 BASIC DEFINITIONS AND RIGID MOTION Representing and 20 G-CO Congruence 1, 2, 3, 4, 5, 6, 7, 8 Combining Transformations Analyzing Congruency Proofs G2 GEOMETRIC RELATIONSHIPS AND PROPERTIES Evaluating Statements 15 G-CO Congruence 9, 10, 11 About Length and Area G-C Circles 3 Inscribing and Circumscribing Right Triangles G3 SIMILARITY Geometry Problems: 20 G-SRT Similarity, Right Triangles, and Trigonometry 1, 2, 3, Circles and Triangles 4, 5 Proofs of the Pythagorean Theorem M1 GEOMETRIC MODELING 1 Solving Geometry 7 G-MG Modeling with Geometry 1, 2, 3 Problems: Floodlights G4 COORDINATE GEOMETRY Finding Equations of 15 G-GPE Expressing Geometric Properties with Equations 4, 5, Parallel and 6, 7 Perpendicular Lines G5 CIRCLES AND CONICS Equations of Circles 1 15 G-C Circles 1, 2, 5 Equations of Circles 2 G-GPE Expressing Geometric Properties with Equations 1, 2 Sectors of Circles G6 GEOMETRIC MEASUREMENTS AND DIMENSIONS Evaluating Statements 15 G-GMD 1, 3, 4 About Enlargements (2D & 3D) 2D Representations of 3D Objects G7 TRIONOMETRIC RATIOS Calculating Volumes of 15 G-SRT Similarity, Right Triangles, and Trigonometry 6, 7, 8 Compound Objects M2 GEOMETRIC MODELING 2 Modeling: Rolling Cups 10 G-MG Modeling with Geometry 1, 2, 3 TOTAL: 144 HIGH SCHOOL OVERVIEW Algebra 1 Geometry Algebra 2 A0 Introduction G0 Introduction and A0 Introduction Construction A1 Modeling With Functions G1 Basic Definitions and Rigid -
Analytical Solid Geometry
chap-03 B.V.Ramana August 30, 2006 10:22 Chapter 3 Analytical Solid Geometry 3.1 INTRODUCTION Rectangular Cartesian Coordinates In 1637, Rene Descartes* represented geometrical The position (location) of a point in space can be figures (configurations) by equations and vice versa. determined in terms of its perpendicular distances Analytical Geometry involves algebraic or analytic (known as rectangular cartesian coordinates or sim- methods in geometry. Analytical geometry in three ply rectangular coordinates) from three mutually dimensions also known as Analytical solid** geom- perpendicular planes (known as coordinate planes). etry or solid analytical geometry, studies geometrical The lines of intersection of these three coordinate objects in space involving three dimensions, which planes are known as coordinate axes and their point is an extension of coordinate geometry in plane (two of intersection the origin. dimensions). The three axes called x-axis, y-axis and z-axis are marked positive on one side of the origin. The pos- itive sides of axes OX, OY, OZ form a right handed system. The coordinate planes divide entire space into eight parts called octants. Thus a point P with coordinates x,y,z is denoted as P (x,y,z). Here x,y,z are respectively the perpendicular distances of P from the YZ, ZX and XY planes. Note that a line perpendicular to a plane is perpendicular to every line in the plane. Distance between two points P1(x1,y1,z1) and − 2+ − 2+ − 2 P2(x2,y2,z2)is (x2 x1) (y2 y1) (z2 z1) . 2 + 2 + 2 Distance from origin O(0, 0, 0) is x2 y2 z2. -
Points, Lines, and Planes a Point Is a Position in Space. a Point Has No Length Or Width Or Thickness
Points, Lines, and Planes A Point is a position in space. A point has no length or width or thickness. A point in geometry is represented by a dot. To name a point, we usually use a (capital) letter. A A (straight) line has length but no width or thickness. A line is understood to extend indefinitely to both sides. It does not have a beginning or end. A B C D A line consists of infinitely many points. The four points A, B, C, D are all on the same line. Postulate: Two points determine a line. We name a line by using any two points on the line, so the above line can be named as any of the following: ! ! ! ! ! AB BC AC AD CD Any three or more points that are on the same line are called colinear points. In the above, points A; B; C; D are all colinear. A Ray is part of a line that has a beginning point, and extends indefinitely to one direction. A B C D A ray is named by using its beginning point with another point it contains. −! −! −−! −−! In the above, ray AB is the same ray as AC or AD. But ray BD is not the same −−! ray as AD. A (line) segment is a finite part of a line between two points, called its end points. A segment has a finite length. A B C D B C In the above, segment AD is not the same as segment BC Segment Addition Postulate: In a line segment, if points A; B; C are colinear and point B is between point A and point C, then AB + BC = AC You may look at the plus sign, +, as adding the length of the segments as numbers. -
1 Paper Rom the Problem of Solid Geometry (Klaus Volkert, University
Paper Rom The problem of solid geometry (Klaus Volkert, University of Cologne and Archives Henri Poincaré Nancy) Some history In Euclid’s “Elements” solid geometry is studied in books XI to XIII. Here Euclid gives a systematic treatment of geometry in space focussing on polyhedra. He discusses basic notions like “being parallel” and “being orthogonal”, gives some simple constructions (like the perpendicular from a point to a plane), discusses the problem of creating a vertex and gives some hints on volume using equidecomposability (in modern terms). Book XIII is devoted to the construction of the five Platonic solids and the proof that there are no more regular polyhedra. Certainly there were some gaps in Euclid’s treatment but not much work was done on solid geometry until the times of Kepler. In particular there was no conceptual analysis of solids – that is a decomposition of them into units of lower dimensions: they were constructed but not analyzed. Euler (1750) was very surprised than he noticed that he was the first to do so. In his “Harmonice mundi” Kepler formulated the theory of Archimedean solids, a more or less new class of semi-regular polyhedra. Picturing polyhedra was a favourite occupation of artists since the introduction of perspective but without a theoretical interest. In Euclid’s “Elements” there is a strict separation between plane geometry (books I to IV, VI) and solid geometry (books XI to XIII) [of course the results of plane geometry are used also in solid geometry and there are also results of plane geometry in the books dedicated to stereometry – in particular on the regular pentagon] which marked the development afterwards. -
Lesson 5: Three-Dimensional Space
NYS COMMON CORE MATHEMATICS CURRICULUM Lesson 5 M3 GEOMETRY Lesson 5: Three-Dimensional Space Student Outcomes . Students describe properties of points, lines, and planes in three-dimensional space. Lesson Notes A strong intuitive grasp of three-dimensional space, and the ability to visualize and draw, is crucial for upcoming work with volume as described in G-GMD.A.1, G-GMD.A.2, G-GMD.A.3, and G-GMD.B.4. By the end of the lesson, students should be familiar with some of the basic properties of points, lines, and planes in three-dimensional space. The means of accomplishing this objective: Draw, draw, and draw! The best evidence for success with this lesson is to see students persevere through the drawing process of the properties. No proof is provided for the properties; therefore, it is imperative that students have the opportunity to verify the properties experimentally with the aid of manipulatives such as cardboard boxes and uncooked spaghetti. In the case that the lesson requires two days, it is suggested that everything that precedes the Exploratory Challenge is covered on the first day, and the Exploratory Challenge itself is covered on the second day. Classwork Opening Exercise (5 minutes) The terms point, line, and plane are first introduced in Grade 4. It is worth emphasizing to students that they are undefined terms, meaning they are part of the assumptions as a basis of the subject of geometry, and they can build the subject once they use these terms as a starting place. Therefore, these terms are given intuitive descriptions, and it should be clear that the concrete representation is just that—a representation. -
Tilted Planes and Curvature in Three-Dimensional Space: Explorations of Partial Derivatives
Tilted Planes and Curvature in Three-Dimensional Space: Explorations of Partial Derivatives By Andrew Grossfield, Ph. D., P. E. Abstract Many engineering students encounter and algebraically manipulate partial derivatives in their fluids, thermodynamics or electromagnetic wave theory courses. However it is possible that unless these students were properly introduced to these symbols, they may lack the insight that could be obtained from a geometric or visual approach to the equations that contain these symbols. We accept the approach that just as the direction of a curve at a point in two-dimensional space is described by the slope of the straight line tangent to the curve at that point, the orientation of a surface at a point in 3-dimensional space is determined by the orientation of the plane tangent to the surface at that point. A straight line has only one direction described by the same slope everywhere along its length; a tilted plane has the same orientation everywhere but has many slopes at each point. In fact the slope in almost every direction leading away from a point is different. How do we conceive of these differing slopes and how can they be evaluated? We are led to conclude that the derivative of a multivariable function is the gradient vector, and that it is wrong and misleading to define the gradient in terms of some kind of limiting process. This approach circumvents the need for all the unnecessary delta-epsilon arguments about obvious results, while providing visual insight into properties of multi-variable derivatives and differentials. This paper provides the visual connection displaying the remarkably simple and beautiful relationships between the gradient, the directional derivatives and the partial derivatives. -
SOLID GEOMETRY CAMBRIDGE UNIVERSITY PRESS Eon^On: FETTER LANE, E.G
QA UC-NRLF 457 ^B 557 i35 ^ Ml I 9^^ soLiTf (itlOMK'l'RV BY C. GODFREY, HEAD M STER CF THE ROY I ^1 f i ! i-ORMERI.Y ; EN ;R MAI :: \: i^;. ; \MNCHEST1-R C(.1J,E(;E an:; \\\ A. SIDDON , MA :^1AN r MASTER .AT ..\:--:: : ', l-ELLi)V* i OF JESL'S COI.' E, CAMf. ^'ambridge : at tlie 'Jniversity Press 191 1 IN MEMORIAM FLORIAN CAJORI Q^^/ff^y^-^ SOLID GEOMETRY CAMBRIDGE UNIVERSITY PRESS Eon^on: FETTER LANE, E.G. C. F. CLAY, Manager (fFtjinfturgi) : loo, PRINCES STREET iSerlin: A. ASHER AND CO. ILjipjig: F. A. BROCKHAUS ^tia lork: G. P. PUTNAM'S SONS iSombas anU Calcutta: MACMILLAN AND CO., Ltd. A /I rights resei'ved SOLID GEOMETRY BY C. GODFREY, M.V.O. ; M.A. w HEAD MASTER OF THE ROYAL NAVAL COLLEGE, OSBORNE FORMERLY SENIOR MATHEMATICAL MASTER AT WINCHESTER COLLEGE AND A. W. SIDDONS, M.A. ASSISTANT MASTER AT HARROW SCHOOL LATE FELLOW OF JESUS COLLEGE, CAMBRIDGE Cambridge : at the University Press 191 1 Camfariljge: PRINTED BY JOHN CLAY, M.A. AT THE UNIVERSITY PRESS. CAJORl PREFACE "It is a great defect in most school courses of geometry " that they are entirely confined to two dimensions. Even *' if solid geometry in the usual sense is not attempted, every ''occasion should be taken to liberate boys' minds from "what becomes the tyranny of paper But beyond this "it should be possible, if the earlier stages of the plane "geometry work are rapidly and effectively dealt with as "here suggested, to find time for a short course of solid " geometry.