[cot (90°-θ) sin (180°-θ) sec (360°-θ)]/ [tan (180°+ θ) sec (-θ) cos (90° + θ)] cot (90°- θ) = Using the identity cot (90°- θ) = tan (θ). sin (180°- θ) = Using the identity sin (180° - θ) = sin (θ). sec (360°- θ) = Using the identity sec (360° - θ) = sec (θ). tan (180°+ θ) =Using the identity tan (180°+ θ) = tan (θ). sec (-θ) = Using the identity sec (-θ) = sec (θ). cos (90°+ θ) = Using the identity cos (90°+ θ) = -sin(θ). Now – = [tan (θ) sin(θ) sec(θ)]/[tan(θ) sec(θ) ( -sin(θ)] =sin(θ) /- sin(θ) =-1