Welcome to 9math!
Posted September 18th, 2007 by IsoscelThis site is for those who are interested in mathematics, whether they want to study it for school or as a hobby.
If you have math questions you can ask them on the forum.
On this site you can write nice mathematical expressions and equations by using Latex and the visual Equation Editor:
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You can use the mouse to play with the interactive geometry figures.
You can also draw functions' graphs fast:
If you wish to learn new notions and tricks you can read the documentation (Algebra, Analysis, Arithmetic, Geometry) that we are developing.
Look at the recent posts to keep up with the latest activity.
Also read the FAQ and Help for more information.
Feuerbach Points
Posted July 5th, 2008 by Structure[geo]
(point A 74 219)
(point B 248 129)
(point C 141 262)
(line AB A B)
(line BC B C)
(line CA C A)
(bisectorpoint A1 C A B)
(bisectorpoint B1 A B C)
(bisectorpoint C1 B C A)
(segment AA1 A A1)
(segment BB1 B B1)
(segment CC1 C C1)
(perpendicular ea A AA1)
(perpendicular eb B BB1)
(perpendicular ec C CC1)
(intersect I AA1 BB1)
(intersect I1 ea eb)
(intersect I2 eb ec)
(intersect I3 ec ea)
(projection M1 I1 CA)
(projection M2 I2 AB)
(projection M3 I3 BC)
(circle T1 I1 M1)
(circle T2 I2 M2)
(circle T3 I3 M3)
(projection M I AB)
(circle T I M)
(middle D B C)
Point of Feuerbach
Posted July 5th, 2008 by StructureLet ABC a triangle and consider the incircle of center I and the nine points circle of Euler. The incircle is interior tangent to the Euler circle in a point called Feuerbach point.
