Prove that : `4\ R\ sin AsinB\ sin C=acosA+b\ cos B+c cosCdot`

If A+B+C=(pi)/(2) ,prove that: sin 2A+"sin" 2B+"sin" 2C=4 cosA cos B cos C.

If A + B + C = (pi)/(2) , prove that sin 2A + sin 2B + sin 2C = 4 cos A cos B cos C

If A + B + C =180^@ , prove that : sin^2 A+ sin^2 B+sin^2 C=2 (1+cos A cos B cos C) .

If A + B + C= pi , prove that sin 2A + sin 2B -sin 2C =4cos A cos B sin C

If A+B+C=pi , prove that sin 2A+sin 2B-sin 2C=4 cos A cos B sin C

If A+B+C=180^@ prove that sin A+sin B+sin C=4 "cos" A/2 "cos" B/2 "cos" C/2

If A, B, C are angles of a triangle , prove that sin 2A+sin 2B-sin 2C=4cos Acos B sin C

If A+B+C=pi/2 prove the following (i) sin 2A+sin 2B +sin 2C=4 cos A cos B cos C (ii) cos 2A +cos 2B+cos 2C=1+4 sin A sin B sin C.

If A+B+C=pi , prove that sin 2A-sin 2B+sin 2C=4cos Asin B cos C.

Prove that ( b- a cos C) sin A = a cos A sin C