Heptagonal triangle and trigonometric identities - Kai Wang We will study the trigonometric identities for heptagonal triangles. Let a < b < c be the heptagonal triangle’s sides and let R be the circumradius. We will prove the following: 2b^2 – a^2 = √7bR, 2c^2 – b^2= √7cR, 2a^2 – c^2 = −√7aR. We will also prove the following trigonometric formula: 4 sin 2kπ/7 – tan kπ/7 = √7for k = 1,2, 4 and -√7 for k = 3,5,6. ✪ ✪ ✪ ✪ ✪ Link tải tài liệu: LINK TẢI TÀI LIỆU Theo LTTK Education
