Euclidean geometry | Theorems about triangles | Conic sections

Droz-Farny line theorem

In Euclidean geometry, the Droz-Farny line theorem is a property of two perpendicular lines through the orthocenter of an arbitrary triangle. Let be a triangle with vertices , , and , and let be its orthocenter (the common point of its three altitude lines. Let and be any two mutually perpendicular lines through . Let , , and be the points where intersects the side lines , , and , respectively. Similarly, let Let , , and be the points where intersects those side lines. The Droz-Farny line theorem says that the midpoints of the three segments , , and are collinear. The theorem was stated by Arnold Droz-Farny in 1899, but it is not clear whether he had a proof. (Wikipedia).

Droz-Farny line theorem
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Lionel Pournin: Algorithmic combinatorial and geometric aspects of linear optimization

The simplex and interior point methods are currently the most computationally successful algorithms for linear optimization. While the simplex methods follow an edge path, the interior point methods follow the central path. The algorithmic issues are closely related to the combinatorial an

From playlist Workshop: Tropical geometry and the geometry of linear programming

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Dimitri Zvonkine - On two ELSV formulas

The ELSV formula (discovered by Ekedahl, Lando, Shapiro and Vainshtein) is an equality between two numbers. The first one is a Hurwitz number that can be defined as the number of factorizations of a given permutation into transpositions. The second is the integral of a characteristic class

From playlist 4th Itzykson Colloquium - Moduli Spaces and Quantum Curves

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Limit of f(x,y)

Limit of functions of two variables. We show how to prove a limit does not exist. Free ebook http://tinyurl.com/EngMathYT

From playlist Several Variable Calculus / Vector Calculus

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Determining Limits of Trigonometric Functions

An introductory video on determining limits of trigonometric functions. http://mathispower4u.wordpress.com/

From playlist Limits

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Rahim Moosa: Around Jouanolou-type theorems

Abstract: In the mid-90’s, generalising a theorem of Jouanolou, Hrushovski proved that if a D-variety over the constant field C has no non-constant D-rational functions to C, then it has only finitely many D-subvarieties of codimension one. This theorem has analogues in other geometric con

From playlist Combinatorics

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Calculus 5.3 The Fundamental Theorem of Calculus

My notes are available at http://asherbroberts.com/ (so you can write along with me). Calculus: Early Transcendentals 8th Edition by James Stewart

From playlist Calculus

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Vacuum Tube Computer P.05 – Vacuum Fluorescent Displays

UPDATE ABOUT PLATE BRIGHTNESS WITH DC FILAMENT: My description of why the brightness shifts across the length of the VFD is incorrect, though the brightness does indeed shift. I believe it actually shifts in the opposite direction, with the plates above the negative end being brighter an

From playlist Vacuum Tube Computer

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Christian Gérard - Construction of Hadamard states for Klein‐Gordon fields

We will review a new construction of Hadamard states for quantized Klein-­Gordon fields on curved spacetimes, relying on pseudo differential calculus on a Cauchy surface. We also present some work in progress where Hadamard states are constructed from traces of Klein-­Gordon fields on a ch

From playlist Ecole d'été 2014 - Analyse asymptotique en relativité générale

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F. Loray - Painlevé equations and isomonodromic deformations II (Part 1)

Abstract - In these lectures, we use the material of V. Heu and H. Reis' lectures to introduce and study Painlevé equations from the isomonodromic point of view. The main objects are rank 2 systems of linear differential equations on the Riemann sphere, or more generally, rank 2 connection

From playlist Ecole d'été 2019 - Foliations and algebraic geometry

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Evaluate the limit with tangent

👉 Learn how to evaluate the limit of a function involving trigonometric expressions. The limit of a function as the input variable of the function tends to a number/value is the number/value which the function approaches at that time. The limit of a function is usually evaluated by direct

From playlist Evaluate Limits with Trig

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Learn to evaluate the limit of tangent

👉 Learn how to evaluate the limit of a function involving trigonometric expressions. The limit of a function as the input variable of the function tends to a number/value is the number/value which the function approaches at that time. The limit of a function is usually evaluated by direct

From playlist Evaluate Limits with Trig

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Measurement-powered engines by Alexia Aufeves

PROGRAM CLASSICAL AND QUANTUM TRANSPORT PROCESSES : CURRENT STATE AND FUTURE DIRECTIONS (ONLINE) ORGANIZERS: Alberto Imparato (University of Aarhus, Denmark), Anupam Kundu (ICTS-TIFR, India), Carlos Mejia-Monasterio (Technical University of Madrid, Spain) and Lamberto Rondoni (Polytechn

From playlist Classical and Quantum Transport Processes : Current State and Future Directions (ONLINE)2022

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Riemann Sum Defined w/ 2 Limit of Sums Examples Calculus 1

I show how the Definition of Area of a Plane is a special case of the Riemann Sum. When finding the area of a plane bound by a function and an axis on a closed interval, the width of the partitions (probably rectangles) does not have to be equal. I work through two examples that are rela

From playlist Calculus

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My Father Kidnapped A Politician (True Crime Documentary) | Real Stories

In October 1970, members of the Front de libération du Québec kidnapped minister Pierre Laporte, unleashing an unprecedented crisis in Quebec. Fifty years later, Félix Rose tries to understand what led his father and uncle to commit these acts. From The Rose Family (Les Rose) Twitter: ht

From playlist True Crime Stories

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Limits of Functions of Two Variables

http://mathispower4u.wordpress.com/

From playlist Limits

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What is Green's theorem? Chris Tisdell UNSW

This lecture discusses Green's theorem in the plane. Green's theorem not only gives a relationship between double integrals and line integrals, but it also gives a relationship between "curl" and "circulation". In addition, Gauss' divergence theorem in the plane is also discussed, whic

From playlist Vector Calculus @ UNSW Sydney. Dr Chris Tisdell

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algebraic geometry 3 Bezout, Pappus, Pascal

This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It gives more examples and applications of algebraic geometry, including Bezout's theorem, Pauppus's theorem, and Pascal's theorem.

From playlist Algebraic geometry I: Varieties

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algebraic geometry 16 Desargues's theorem

This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It covers Desargues's theorem and duality of projective space.

From playlist Algebraic geometry I: Varieties

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Parallel Lines and Angle Pairs

Introduce and prove theorems involving angle pairs formed by parallel lines and transversals. Demonstrate two-column proofs and work out problems with algebraic expressions.

From playlist Geometry

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Multivariable Calculus | Showing a limit does not exist

We introduce the notion of the limit of a function with more than one variable and provide a strategy for showing that the limit does not exist. http://www.michael-penn.net http://www.randolphcollege.edu/mathematics/

From playlist Multivariable Calculus

Related pages

Euclidean geometry | Line (geometry) | Point (geometry) | Altitude (triangle) | Orthocenter | Plane (geometry) | Pole and polar