Respuesta :

Wallind11

Step-by-step explanation:

sin(A − B) = sin A cos B − cos A sin B

sin50°cos 40° - cos50°sin 40°

= sin(50-40)°

=sin10°

cos(A + B) = cos A cos B − sin A sin B

cos75°cos 15° - sin75°sin 15°

= cos(75+15)° = cos90° = 0