Unsolved problems in number theory | Arithmetic problems of plane geometry | Triangle geometry | Elliptic curves
In number theory, a congruent number is a positive integer that is the area of a right triangle with three rational number sides. A more general definition includes all positive rational numbers with this property. The sequence of (integer) congruent numbers starts with 5, 6, 7, 13, 14, 15, 20, 21, 22, 23, 24, 28, 29, 30, 31, 34, 37, 38, 39, 41, 45, 46, 47, 52, 53, 54, 55, 56, 60, 61, 62, 63, 65, 69, 70, 71, 77, 78, 79, 80, 84, 85, 86, 87, 88, 92, 93, 94, 95, 96, 101, 102, 103, 109, 110, 111, 112, 116, 117, 118, 119, 120, ... (sequence in the OEIS)Congruent number table: n ≤ 120 For example, 5 is a congruent number because it is the area of a (20/3, 3/2, 41/6) triangle. Similarly, 6 is a congruent number because it is the area of a (3,4,5) triangle. 3 and 4 are not congruent numbers. If q is a congruent number then s2q is also a congruent number for any natural number s (just by multiplying each side of the triangle by s), and vice versa. This leads to the observation that whether a nonzero rational number q is a congruent number depends only on its residue in the group , where is the set of nonzero rational numbers. Every residue class in this group contains exactly one square-free integer, and it is common, therefore, only to consider square-free positive integers, when speaking about congruent numbers. (Wikipedia).
Number Theory | Congruence Modulo n -- Definition and Examples
We define the notion of congruence modulo n among the integers. http://www.michael-penn.net
From playlist Modular Arithmetic and Linear Congruences
Number Theory | Integer Congruence Example 1
We give a few examples involving integer congruence.
From playlist Modular Arithmetic and Linear Congruences
Using Two Congruent Triangles to Find the Value of X and Y
👉 Learn how to solve for unknown variables in congruent triangles. Two or more triangles are said to be congruent if they have the same shape and size. When one of the values of a pair of congruent sides or angles is unknown and the other value is known or can be easily obtained, then the
From playlist Congruent Triangles
Identifying congruent parts between two polygons
👉 Learn how to solve with similar polygons. Two polygons are said to be similar if the corresponding angles are congruent (equal). When two polygons are similar the corresponding sides are proportional. Knowledge of the length of the sides or the proportion of the side lengths of one of th
From playlist Congruent Polygons
Using Congruent Triangles to Determine the Value of X
👉 Learn how to solve for unknown variables in congruent triangles. Two or more triangles are said to be congruent if they have the same shape and size. When one of the values of a pair of congruent sides or angles is unknown and the other value is known or can be easily obtained, then the
From playlist Congruent Triangles
What is the Definition of Congruent Triangles - Congruent Triangles
👉 Learn about congruent triangles theorems. Two or more triangles (or polygons) are said to be congruent if they have the same shape and size. There are many methods to determine whether two triangles are congruent. Some of the methods include: (1) The SSS (Side Side Side) congruency the
From playlist Congruent Triangles
Congruent and Similar Triangles
working with similiar triangles, determining similar triangles http://mathispower4u.wordpress.com/
From playlist Geometry Basics
Determining if Two Triangles are Congruent by Plotting Points
👉 Learn how to show whether two triangles are congruent from the coordinate (x-y) plane. Two or more triangles are said to be congruent if they have the same shape and size. To show whether two triangles whose points on the coordinate plane are given we first plot the points on the coordin
From playlist Congruent Triangles
Determine the the Values of X and Y Using Congurent Triangles
👉 Learn how to solve for unknown variables in congruent triangles. Two or more triangles are said to be congruent if they have the same shape and size. When one of the values of a pair of congruent sides or angles is unknown and the other value is known or can be easily obtained, then the
From playlist Congruent Triangles
Triangle Congruence Theorems, Two Column Proofs, SSS, SAS, ASA, AAS Postulates, Geometry Problems
This geometry video tutorial provides a basic introduction into triangle congruence theorems. It explains how to prove if two triangles are congruent using the SSS, SAS, ASA, and AAS postulate using two column proofs. Here is a list of topics contained in the statements and reasons of th
From playlist Geometry Video Playlist
CPCTC Geometry Proofs Made Easy, Triangle Congruence - SSS, SAS, ASA, & AAS, Two Colmn Proofs
This video tutorial provides a basic introduction into CPCTC geometry proofs. CPCTC stands for "corresponding parts of congruent triangles are congruent" It's the step that comes right after proving the congruence of two triangles. Some triangle congruence theorems you need to know are
From playlist Geometry Video Playlist
Introduction to number theory lecture 9: Congruences
This lecture is part of my Berkeley math 115 course "Introduction to number theory" For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj53L8sMbzIhhXSAOpuZ1Fov8 This lecture revies congruences, proves Fermat's theorem, and gives some applications of it
From playlist Introduction to number theory (Berkeley Math 115)
Two Column Proofs With Parallelograms, Isosceles Trapezoids, Rhombuses, and Kites - Geometry
This geometry video tutorial provides a basic introduction into proving parallelograms, isosceles trapezoids, rhombuses, and kites using two column proofs. Theorems used in this video include the vertical angle theorem, alternate interior angles, parallel lines, SAS and AAS triangle congr
From playlist Geometry Video Playlist
In this video we do continue our introduction to congruences, and we discuss and prove some of the basic properties that make congruences very useful. The content of this video corresponds to Section 4.2 of my book "Number Theory and Geometry" which you can find here: https://alozano.clas
From playlist Number Theory and Geometry
A number theory problem from Morocco!
We solve a viewer suggested number theory problem from a math contest in Morocco. Please Subscribe: https://www.youtube.com/michaelpennmath?sub_confirmation=1 Merch: https://teespring.com/stores/michael-penn-math Personal Website: http://www.michael-penn.net Randolph College Math: http:/
From playlist Math Contest Problems
Introduction to number theory lecture 10. Fermat's theorem
This lecture is part of my Berkeley math 115 course "Introduction to number theory" For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj53L8sMbzIhhXSAOpuZ1Fov8 We prove Fermat's theorem about powers mod p. The textbook is "An introduction to the the
From playlist Introduction to number theory (Berkeley Math 115)
Lecture 7 - Relative Primality
This is Lecture 7 of the CSE547 (Discrete Mathematics) taught by Professor Steven Skiena [http://www.cs.sunysb.edu/~skiena/] at Stony Brook University in 1999. The lecture slides are available at: http://www.cs.sunysb.edu/~algorith/math-video/slides/Lecture%2007.pdf More information may
From playlist CSE547 - Discrete Mathematics - 1999 SBU
Introduction to number theory lecture 12 Wilson's theorem
This lecture is part of my Berkeley math 115 course "Introduction to number theory" For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj53L8sMbzIhhXSAOpuZ1Fov8 We discuss Wilsons theorem that (p-1)! = 1 mod p. The textbook is "An introduction to the
From playlist Introduction to number theory (Berkeley Math 115)
Shou-Wu Zhang: Congruent number problem and BSD conjecture
Abstract : A thousand years old problem is to determine when a square free integer n is a congruent number ,i,e, the areas of right angled triangles with sides of rational lengths. This problem has a some beautiful connection with the BSD conjecture for elliptic curves En:ny2=x3−x. In fact
From playlist Jean-Morlet Chair - Research Talks - Prasad/Heiermann
Proving Parallelograms With Two Column Proofs - Geometry
This geometry video tutorial provides a basic introduction into two column proofs with parallelograms. It explains the different ways of proving parallelograms. Here are five ways: 1. opposite sides must be parallel. 2. Opposite sides must be congruent. 3. opposite angles must be c
From playlist Geometry Video Playlist