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

Prove that a cos A + b cos B + c cos C = 4 R sin A sin B sin C.

In a DeltaA B C , prove the following : a\ cos A+b\ cos B+c cos C=2bsinA sin\ Cdot

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 : a^2 +b^2 +c^2 = 2 (bc cos A + ca cos B + ab cos C) .

In DeltaABC , prove that: acosA+bcosB=(c)cos(A-B)

In any DeltaABC , a cos A +b cos B + c cos C =

In any DeltaABC , prove that acos(A+B+C)-bcos(B+A)-c""cos(A+C)=0

In any DeltaABC , prove that : (cos A)/a + a/(bc) = (cos B)/b + b/(ca) = (cos c)/c + c/(ab)

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 DeltaABC , prove that (sin B)/(sin(B+C) ) = b/a