cos62°+cos33°=2(cos(62°+33°)/2)*(cos(62°-33°)/2)=
2cos47.5°*cos14.5°
cos62°-cos33°=-2(sin(62°+33°)/2)*(sin(62°-33°)/2)=
-2sin47.5°*sin14.5°
cos62°+cos33°=2(cos(62°+33°)/2)*(cos(62°-33°)/2)=
2cos47.5°*cos14.5°
cos62°-cos33°=-2(sin(62°+33°)/2)*(sin(62°-33°)/2)=
-2sin47.5°*sin14.5°