`cosA+cos(12 0^(@)+A)+cos(12 0^(@)-A)=`

cosA+cos(120^(@)-A)+cos(120^(@)+A)=0

cosA+cos(120^(@)-A)+cos(120^(@)+A)=0

cosA + cos (A + 120) + cos (120 - A) = 0

Prove that cos(60^(@)+A) + cos(60^(@)-A)-cosA=0

Prove that cos(120^@-A)+cosA+cos(120^@+A)=0 .

Prove that a) (sin3A + sinA)sinA+(cos3A-cosA) cosA=0 b) cos20^(@)cos40^(@)cos80^(@)=1/8

cos48^(@)*cos12^(@)=

cos48^(@)*cos12^(@)=

(cos 12^(@) - sin 12^(@))/(cos 12^(@) + sin 12) + (sin 147^(@))/(cos 147^(@))= ................... A) 1 B) -1 C) 0 D) sqrt3

If the distance between the points P(a cos48^(@),0) and Q(0,a cos12^(@)) is d, then d^(2)-a^(2)=