Question

1 . given A = 60 ° and B = 30° , prove that :
b) cos ( A - B ) = cos A cos B + sin A sin B
please answer the questions​

Answer 1

Answer:

hey mate here is your answer

Answer 2

Step-by-step explanation:

Given: A=60° and B =30°

Now, LHS = Cos (A+B)

⇒ Cos (60° + 30°)

⇒ Cos (90°)

⇒ 0 [∵ cos 90° = 0] Now, RHS = Cos A Cos B – Sin A Sin B

⇒ cos(60°) cos(30°) – sin(60°) sin (30°)

⇒ 0 ∴ LHS = RHS

Hence Proved