... (1) p dng lm bi 26, 27/88 Bi v nh 28, 29, 30, 31/ 89 VD5: N = 90 0 - M = 90 0 - 510 = 390 LN = LM tan M = 2,8 tan510 3,458 LM 2,8 MN = 4,4 49 0,6 293 cos 51 Lu ý: (SGK trang 78) Tun Ngy son: ... 38/SGK trang 95 IB = IK tan(500 + 150) = 380 tan650 814 ,9 (m) IA = IK tan500 = 380 tan500 452 ,9 (m) Vy khong cỏch gia thuyn A v B l: AB = IB - IA = 814 ,9 - 452 ,9 = 362 (m) Bi 40/SGK trang 95 Chiu ... N = 90 0- M = 90 0 510 = 390 LN = LM tanM = 2,8 tan510 3,458 Cú LM = cos510 LM MN = 4, 49 cos510 3) Cng c (7 pỳt ) HS gii bi 27a ( Sgk) 4/ Hng dn v nh: (1 phỳt) a) Lm cỏc bi tp: 27, 28, 29 trang...