Question

right to say cos(60° + 30) = cos 60° cos30° - sin 60° sin 30°.​

Answer 1

Answer:

LHS:

cos(60+30)

=> cos(90)

=>0

RHS:

cos60cos30-sin60sin30

=>(1/2*$\sqrt{3}$/2 )- ($\sqrt{3}$/2*1/2)

=> 0

Therefore LHS = RHS

Hence we can say that cos(60+30)=cos60cos30-sin60sin30

Answer 2

Answer:

You are correct .

This identity is given as

cos(A + B) = cos A . cos B - sin A . sin B

Here your answer will be cos 90° = 0

I hope it helped u