Show that in a triangle ABC,`(b^2-c^2)/(cosB+cosC)+(c^2-a^2)/(cosC+cosA)+(a^2-b^2)/(cosA+cosB)=0`

Show that in a triangle ABC, (b^2-c^2)/a^2sin2A+(c^2-a^2)/b^2sin2B+(a^2-b^2)/c^2sin2C=0

Show that in a triangle ABC, (asin(B-C))/(b^2-c^2)=(bsin(C-A))/(c^2-a^2)=(csin(A-B))/(a^2-b^2)

Show that in a triangle ABC, a^2-2abcos(60^@+C)=c^2-2bc cos(60^@+A)

In a triangle ABC, prove that (b^2 - c^2) cot A + (c^2 -a^2) cot B+ (a^2-b^2) cot C = 0

Prove that in a triangle ABC, bc cos A + ca cos B +ab cos C= 1/2(a^2+b^2+c^2)

Show that in a triangle ABC, a^2(sin^2B-sin^2C)+b^2(sin^2C-sin^2A)+c^2(sin^2A-sin^2B)=0

Show that in a triangle ABC, a^3sin(B-C)+b^3sin(C-A)+c^3sin(A-B)=0

Prove that in a quadrilateral ABCD, cosA+cosB+cosC+cosD-4cos((A+B)/2)cos((A+C)/2)cos((A+D)/2)=0

Show that in a triangle ABC, asin(A/2)sin((B-C)/2)+bsin(B/2)sin((C-A)/2)+csin(C/2)sin((A-B)/2)=0

Choose the correct option In a triangle ABC, sin((A+B)/2) is equal to a) cos(B-C)/2 b) cos(C-A)/2 c) cos(A/2) d) cos (C/2)