Respuesta :

ghanami
Hello :
 sin(−θ) = - sin(θ)
 cot(−θ) = - cot(θ)
cot(θ) = cos(θ)/sin(θ)
sin(−θ) cot(-θ) = (- sin(θ))×(-cos(θ)/sin(θ)) = cos(θ)