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, (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, 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

In a triangle ABC, cot A, cot B, cot C are in A.P. Prove that a^2 , b^2 , c^2 are in A.P.

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)

Prove that (sin A+sin B)/(cos A+cos B)=tan((A+B)/2)

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(B-C))/(b^2-c^2)=(bsin(C-A))/(c^2-a^2)=(csin(A-B))/(a^2-b^2)

Prove the following (cos ^2A* sin^2 B)- (sin^2 A* cos ^2B)= cos^2 A- cos ^2B