Just got this in an exam:
I think there's an error though cause I find that they are not equal when I assign values to A, B, and C. Any help? I'm probably wrong
Ok I have checked the information and I left out the first line and you were correct, it only applies to a triangle.
On the level that we do trigenometry, we can do compound angles
Then changing from
Do you perhaps know how i would go about proving this identity using these rules?