Упростите СРОЧНО!!!!!!! cos (p/3+b)*cos(p/3-b)-sin(p/3-b)*sin(p/3+b)

Question

Упростите СРОЧНО!!!!!!!
cos (p/3+b)*cos(p/3-b)-sin(p/3-b)*sin(p/3+b)

Answer 1

Cos(π/3+b)cos(π/3-b)-sin(π/3+b)sin(π/3-b)=cos(π/3+b)