L S = sin x/( 1 + cos x) * ( 1 - cos x ) / ( 1 - cos x ) = = sin x ( 1 - cos x ) / ( 1 - cos² x ) = = ( sin x - sin x cos x ) / sin² x = = sin x / sin² x - ( sin x cos x ) / sin² x = = 1 / sin x - cos x / sin x = csc x - cot x = RS Therefore: LS = RS
