3 cos 28 cos 34 - 3 cos 62 cos 56

Question

3 cos 28 cos 34 - 3 cos 62 cos 56

Answer 1

3cos28cos34-3cos62cos56
Cos28=cos(90-62)=sin62
Cos34=cos(90-56)=sin56
3sin62sin56-3cos62cos56= 3sin(62-56)=3sin6