[sin B sin C],[9*cos^(2)A+cos^(2)B+cos^(2)C=1-2cos A cos B cos C],[=1+sin^(2)B+sin^(2)C=2sin A cos B sin C]

Prove that in triangle ABC,cos^(2)A+cos^(2)B-cos^(2)C=1-2sin A sin B cos C

If DeltaABC , prove that: a) sin^(2)A+sin^(2)B-sin^(2)C=2sinAsinBcosC b) cos^(2)A+cos^(2)B-cos^(2)C=1-2sinAcosBsinC c) cos^(2)A+cos^(2)B+cos^(2)C=1-2cosAcosBcosC

a.cos A + b.cos B + c.cos C = 2a sin B sin C

a cos A + b cos B + c cos C = 2a sin B sin C

If : A+B+C=pi, "then" : 1-cos^(2) A-cos^(2)B-cos^(2)C= A) 2 cos A * cos B * cos C B) 2 sin A * cos B * cos C C) 2 cos A * sin B * cos C D) 2 cos A * cos B * sin C

cos2B + cos2A-cos2C = 1-4sin A sin B cos C

If A+B+C= (pi)/(2) ,prove that: (i) cos^(2)A+cos^(2)B+cos^(2)C=2+2"sin"A "sin"B "sin"C (ii) "sin"^(2)+"sin"^(2)B+"sin"^(2)C=1-2 "sin"A sin B sin C .

If cos(A+B+C)=cos A cos B cos C , then (8sin(B+C)sin(C+A)sin(A+B))/(sin2A sin 2B sin 2C)=

If A+B+C=pi, prove that sin^(2)A+sin^(2)B+sin^(2)C=2(1+cos A cos B cos C)

If A+B+C=90^(@) then cos^(2)A+cos^(2)B+cos^(2)C=2+K sin A sin B sin C then K=