Cos (x-30°) - cos (x+30°)

Question

Cos (x-30°) - cos (x+30°)

Answer 1

Cos(x-60)=cosx cos60=1/2 coxs+sqrt(3)/2 sinx

cos(x+30)=cosx cos30-sinxsin30=sqrt(3)/2 cosx-1/2 sinx

Comments

Спасибо