किसी `DeltaABC` में, सदिश विधि से सिद्ध करें की
`c=a cos B +b cos A`.

In a DeltaABC , if a = 3, b = 5 and c = 7, find cos c

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

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

For any DeltaABC , prove that a(b cos C -c cos B) = b^2 - c^2

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

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

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

In DeltaABC , if b(b +c) = a^(2) and c(c + a) = b^(2) , then |cos A.cos B. cos C| is______