(ii) `(b-c) cos( A/2) = a sin ((B-C)/2)`

If a,b,c are sides opposte to the angles A,B , C then which of the following is correct (1)(b+c)cos((A)/(2))=a sin((B+C)/(2))(2)(b+c)cos((B+C)/(2))=a sin((A)/(2))(3)(b-c)cos((B-C)/(2))=a(cos A)/(2)(4)(b-c)cos((A)/(2))=a sin((B-C)/(2))

In triangle ABC,a,b,c are the lengths of its sides and A,B,C are the angles of triangle ABC .The correct relation is given by (a) (b-c)sin((B-C)/(2))=a(cos A)/(2) (b) (b-c)cos((A)/(2))=as in(B-C)/(2)(c)(b+c)sin((B+C)/(2))=a(cos A)/(2)(d)(b-c)cos((A)/(2))=2a(sin(B+C))/(2)

In a A B C ,\ A D is the bisector of the angle A meeting B C at Ddot If I is the incentre of the triangle, then A I\ : D I is equal to - (s in B+s in C):\ s in A (b) (cos B+cos C): cos A cos((B-C)/2):cos((B+C)/2) (d) sin((B-C)/2):sin((B+C)/2)

In any triangle ABC, show that : 2a cos (B/2) cos (C/2) = (a+b+c) sin (A/2)

In any triangle ABC, prove that (i) (a-b)/( c)=("sin"(A-B)/(2))/("cos"( C)/(2)) (ii) (b-c)/(a)=("sin"(B-C)/(2))/("cos"(A)/(2))

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)

In Delta ABC prove that (a-b)^2 cos^2(C/2) + (a+b)^2 sin^2(C/2) = c^2

cos A + cos B + cos C = 1 + 4sin ((A) / (2)) sin ((B) / (2)) sin ((C) / (2))

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