Question

Решите #3 (2)
Алгебра
Пожалуйста!!!

Answer 1

3.
1) cos(a-b)-cos(a+b)=-2sin(a)sin(-b)=-2sin(a)*(-sin(b))=2sin(a)sin(b)

2) cos(3п/2-а)+cos(п+а)/2sin(a-п/2)cos(-a)+1=-sin(a)-cos(a)/2(cos(a))cos(-a)+1=-sin(a)-cos(a)/-2cos(a)cos(a)+1=-sin(a)-cos(a)/-2cos(a)^2+1=-sin(a)-cos(a)/-(2cos(a)^2-1)=-sin(a)-cos(a)/-cos(2a)=-(cos(a)+sin(a))/cos(a)^2-sin(a)^2=-(cos(a)+sin(a))/(cos(a)-sin(a))(cos(a)*sin(a))=-1/cos(a)-sin(a)=1/cos(a)-sin(a)