Question

cos (A + B) = cos A cos B - sin A sin B.
A- 60 and B-30​​

Answer 1

Step-by-step explanation:

A=60

B= 30

put values

cos A cosB -sinA sin B

cos 60 ×cos 30 - sin 60 ×sin 30= cos ( 60+30)

1/2×root 3/2 - root 3 /2 × 1/2

root 3/4 - root 3 /4

0