Respuesta :

allianaeacepaws

Answer:

--1/2 or -0.5

Step-by-step explanation:

Step-by-step explanation:

cos 30° cos 90° - sin 30° sin 90°

cos 30° = √3/2

cos 90°=0

sin30°= ½

sin 90°=1

= √3/2(0) -½(1)

=-½