Difference between revisions of "2006 IMO Problems"
(→Problem 1) |
(→Problem 1) |
||
Line 1: | Line 1: | ||
==Problem 1== | ==Problem 1== | ||
− | Let <math>ABC be a triangle with incentre I. A point P in the interior of the triangle satisfies < | + | Let <math>ABC</math> be a triangle with incentre I. A point P in the interior of the triangle satisfies <math><PBA</math> + <math><PCA</math> = <math><PBC</math> + <math><PCB</math>. |
Show that AP ≥ AI, and that equality holds if and only if P = I. | Show that AP ≥ AI, and that equality holds if and only if P = I. | ||
Revision as of 22:52, 14 February 2019
Problem 1
Let be a triangle with incentre I. A point P in the interior of the triangle satisfies + = + . Show that AP ≥ AI, and that equality holds if and only if P = I.
Problem 2
Let be a regular 2006-gon. A diagonal of is called good if its endpoints divide the boundary of into two parts, each composed of an odd number of sides of . The sides of are also called good. Suppose has been dissected into triangles by 2003 diagonals, no two of which have a common point in the interior of . Find the maximum number of isosceles triangles having two good sides that could appear in such a configuration.