Dovedeste ca csc4A + csc8A = cot2A-cot8A?

# = Cot2A-RHS cot8A #

# = (Cos2A) / (sin2A) - (cos8A) / (sin8A) #

# = (Cos2Asin8A-cos8Asin2A) / (sin2Asin8A) #

# = Sin (8A-2A) / (sin2Asin8A) #

# = (2cos2Asin6A) / (2cos2Asin2Asin8A) #

# = (Sin8A + sin4A) / (sin4Asin8A) #

# = (Sin8A) / (sin4Asin8A) + (sin4A) / (sin4Asin8A) #

# = 1 / (sin4A) + 1 / (sin8A) #

# = Csc4A + csc8A = LHS #