cos(-cos0)=2sin(c+0)/(2)*(sin n-c)/(2)

Theorem 4:sin A+sin B+sin C=4(cos A)/(2)(cos B)/(2)(cos C)/(2)

(sin2A+sin2B+sin2C)/(cos A+cos B+cos C-1)=((lambda)/(2))(cos A)/(2)(cos B)/(2)(cos C)/(2) then lambda=

Assertion A:In/_ABC,sum(cos A)/(sin B sin C)=2 Reason R:In/_ABC,sin A+sin B+sin C=4(cos A)/(2)(cos B)/(2)(cos C)/(2)

If A+B+C=180^0 , prove that : cos^2( A/2) + cos^2( B/2) + cos^2(C/2) = 2+2 sin(A/2) sin( B/2) sin( C/2)

If A+B+C=180^0 , prove that : cos^2( A/2) + cos^2( B/2) + cos^2(C/2) = 2+2 sin(A/2) sin( B/2) sin( C/2)

(cos^(2)1^(0)-cos^(2)2^(0))/(2sin3^(0)*sin1^(0)) is equal to

sin A + sin B + sin C = cos A + cos B + cos C = 0then (A) cos (AB) = - (1) / (2) (B) sin ^ (2) A + sin ^ (2) B + sin ^ (2) C = 0 (C) sin ^ (2) A + sin ^ (2) B + sin ^ (2) C = (3) / (2) (D) cos ^ (2) A + cos ^ (2) B + cos ^ (2) C = (3) / (2)

(2sin (AC) cos C-sin (A-2C)) / (2sin (BC) cos C-sin (B-2C)) = (sin A) / (sin B)

(2sin (AC) cos C-sin (A-2C)) / (2sin (BC) cos C-sin (B-2C)) = (sin A) / (sin B)

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