Question

It is right to say that cos (60degree -30degree )=cos 60degree cos 30degree - sin 60degree sin 30degree. give reasons​

Answer 1

Step-by-step explanation:

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

Answer 2

Answer:

No, it is not right

Step-by-step explanation:

The correct formula is :

cos(60° - 30°) = cos60°cos30° + sin60°sin30°

It is right because there is a FORMULA :

cos(A - B) = cosAcosB + sinAsinB