Question

Find the whether LHS =RHS for the following (I) sin (60+30)=sin60 cos 30 +sin 30 cos 60 (ii) cos (60+30) =cos 60 cos 30 -sin 60 sin 30

Answer 1

1). LHS sin(60+30) = sin(90)

sin(90) = 1

RHS

sin60 = root 3/2

cos30= root3/2

sin30 = 1/2

cos60= 1/2

root3/2 × root3/2 + 1/2 × 1/2 = 1

so LHS=RHS