Created by the Canadian IMO team during their summer training, to challenge each other.
1.在[latex]\triangle ABC[/latex]中,[latex]\angle BAC=60^{\circ}[/latex]且内切圆分别切[latex]AB,AC[/latex]于[latex]P,Q[/latex].[latex]PC,QB[/latex]交于点[latex]G[/latex].设[latex]r[/latex]为[latex]\triangle BCG[/latex]的外接圆半径,求[latex]\displaystyle \frac{r}{BC}[/latex]的最小值. 继续阅读