In any ` A B C` , prove that: `(b+c)cos A+(c+a)cos B+(a+b)cos C=a+b+c`

In any Delta A B C , prove that: a(b\ cos C-c cosB)=b^2-c^2

In any Delta A B C , prove that: (cos A)/a+(cos B)/b+(cos C)/c=(a^2+b^2+c^2)/(2a b c)

In any DeltaABC , prove that : a cos A + b cos B + c cos C = 2a sin B sin C

In a DeltaA B C prove that cos(A+B)+cos C=0.

In any DeltaABC , prove that (sin B)/(sin C) = (c-a cos B)/(b-a cos C)

In any DeltaABC , prove that : (cos A)/(b cos C + c cos B) + (cos B)/(c cos A + a cos C) + (cos C)/(a cos B + b cos A) = (a^2 + b^2 + c^2)/(2abc)

In any DeltaABC , prove that : (b^2 - c^2)/(cos B + cos C) + (c^2 - a^2)/(cos C + cos A) + (a^2 - b^2)/(cos A + cos B) = 0

In any A B C , prove that: 2{b cos^2(C/2) + c cos^2(B/2)}=a+c+b

In any triangle A B C , prove that following: \ \ bcosB+c\ cos\ C="a c o s"(B-C)

In any DeltaABC , prove that : (b^2 - c^2) cos 2A + (c^2 - a^2) cos 2B + (a^2 - b^2) cos 2C =0