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IN, Factorization & Defactorizat, 6- 53, Factorization & Defactorization, 6- 52, 2A, 2 cos, 图), Basic Mathematics, ЗА), +2 sin, cos, (5A, cos, 台), • cos, Basic Mathematics, 2, (SA, 2 sin, 2, 2A, %3D, (5A, ЗА, +2 sin, 2, 2 sin, 2, Cos, sin, 2, 2 sin A sin 24), (4), (5A, 2 cos A · cos, Taking 2 sin, (3A), 2 sin A· cos, (5A, 2 sin, cos, 2, + cos, cos (-0)= cos 6, (5A, 2 sin, ЗА, 2., cos A, sinA, Cos e, sin, + sin, cot e, sine, C+D, (C-D, cos, 2, cos C+ cos D=2 cos, 2, = cot A = R.H.S., sin A + sin 2A+ sin 3A + sin 4A, cos A + cos 2A - cos 3A - cos 4A, (3A), = cot A, Cos, + cos, 图), (ЗА, sin, + sin, Example 6.41: Prove that :, 2, (sin 80 + sin 20) (cos 60 + cos 40), (sin 60 – sin 40) (cos 80 - cos 20), =- cot 30 - cot 0, C+D, С-D, cos, 2, sin C+ sin D 2 sin, (sin 80 + sin 20) (cos 60 + cos 40), (sin 60 - sin 40) (cos 80- cos 20), (ЗА А, (ЗА, A, Solution :, L.H.S. =, 2, 2 2, cos, 2 cos, (C-D, 2, (C+D, cos, sin C+ sin D = 2 sin, (3A A, +, 2, (ЗА А, 2 2, 2, 2 sin, 2, cos, (C+1, sin C- sin D = 2 cos, sin, 2, (4A), (2A, 2, cos, 2, (C+D), 2 cos, cos C+ cos D 2 cos, 2, cos, 4A, (2A, 2, 2 sin, 2, 2, Cos, 2, C+D, sin, cos C- cos D = 2 sin, Technical Publications - An up thrust for knowledge, TM, TM, Technical Publications -An up thrust for knowledge, common and denominator.