Euler's formula and Poncelet's porism - Lev Emelyanov and Tatiana Emelyanova It is well known that two intersecting circles O(R) and O_1(R_1) are the circumcircle and an excircle respectively of a triangle if and only if the Euler formula d^2=R^2+2RR_1, where d=|OO_1|, holds. We present a possibly new proof and an application to the Poncelet porism. ✪ ✪ ✪ ✪ ✪ Link tải tài liệu: LINK TẢI TÀI LIỆU Theo LTTK Education
