If `A+B+C=(3pi)/2, t h e ncos2A+cos2B+cos2C` is equal to (a) `1-4cos Acos BcosC` (b) `4sinAsinBsinC` (c) `1+2cosAcosBcosC` (d) `1-4sinAsinBsinC`

If A+B+C =(3pi)/(2) , then cos2A+cos2B+cos2C is equal to-

If A+B+C=(3pi)/2, t h e ncos2A+cos2B+cos2C is equal to 1-4cos Acos BcosC 4sinAsinBsinC 1+2cosAcosBcosC 1-4sinAsinBsinC

If A+B+C=(3 pi)/(2), then cos2A+cos2B+cos2C is equal to (A)1-4cos A cos B cos C(B)4sin A sin B sin C(C)1+42cos A cos B cos C(D)1-4sin A sin B sin C

If A+B+C=3pi/2 . Then cos 2A +cos 2B+cos2C is equal to

If A+B+C=(3 pi)/(2), then cos2A+cos2B+cos2C is equal to a.1-4cos A cos B cos C b.4sin A sin B sin C c.1+2cos A cos B cos Cd.1-4sin A sin B sin C

If A+B+C=(3 pi)/(2), then cos2A+cos2B+cos2C is equal to (i) 1-4cos A cos B cos C( is 4sin A sin B sin C (iii) 1+2cos A cos B cos C(iv)1-4sin A sin B sin C

If A+B+C=(3pi)/2 . Then cos 2A +cos 2B+cos2C is equal to ................. A) 1-4 cos A cos B cos C B) 4 sin A sin B sin C C) 1+2 cos A cos B cos C D) 1-4 sin A sin B sin C

If A+B+C=3pi/2 then cos2A+cos2B+cos2C=1-4sinAsinBsinC

If A + B + C =pi , prove that : cos 2A + cos 2B + cos 2C = -1-4 cos A cos B cos C .