Cos (a-b) - cos (a+b)

Question

Cos (a-b) - cos (a+b)

Answer 1

Cosacosb+sinasinb-cosacosb+sinasinb=sinasinb+sinasinb=sinasinb(1+1)=2sinasinb

Answer 2

Cosacosb+sinasinb-cosacosb+sinasinb=2sinasinb