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

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

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 any triangle ABC, prove that : (cosA)/a+ (cosB)/b+(cosC)/c= (a^2+b^2+c^2)/(2abc) .

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

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

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

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

Statement I In any triangle ABC a cos A+b cos B+c cos C le s. Statement II In any triangle ABC sin ((A)/(2))sin ((B)/(2))sin ((C)/(2))le 1/8

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