Prove that, in any triangle ABC, `cos B=(c^2+a^2-b^2)/(2ca)`.

Prove that, in any triangle ABC, cos C=(a^2+b^2-c^2)/(2ab) .

Prove that in any triangle ABC,c=a cos B+b cosA

Prove that in any triangle ABC , c = a cos(360-B) + b cos(360-A)

In a triangle ABC, 2ca sin frac(A-B+C)(2) =

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

In any triangle ABC, prove that cos A= frac{b^2+c^2-a^2}{2bc} .

In any triangle ABC, prove that : (c^2-a^2+b^2) tan A= (a^2-b^2+ c^2) tan B= (b^2-c^2+a^2) tan C .

In any triangle ABC, prove that : a (cos C - cos B) = 2 (b-c) cos^2 frac (A)(2) .

In any triangle ABC, prove that : sin frac (A-B)(2)= (a-b)/c cos frac (C)(2) .

In any triangle ABC, prove that : (b^2-c^2)/(a^2)= sin (B -C)/sin(B+C) .