" In any "/_ABC" ,prove by vector method that "cos B=(c^(2)+a^(2)-)/(2ca)

With the help of vector method, prove that, cosB=(c^2+a^2-b^2)/(2ca)

In any DeltaABC prove by vectors that b^2=c^2+a^2-2 ca cos B.

With usual notations, in any triangle ABC, prove the following by vector method . (i) a^(2)=b^(2)+c^(2)-2bc cos A (ii) b^(2)=c^(2)+a^(2)-2bc cosB (iii) c^(2)=a^(2)+b^(2)-2bc cosC

Prove by vector method that in a Delta ABC, c^(2) = a^(2) + b^(2) - 2ab cos C .

In any Delta ABC, prove that cos C=(a^(2)+b^(2)-c^(2))/(2ab) with the help of vectors

In Delta ABC, prove that cos A=(b^(2)+c^(2)-a^(2))/(2bc) by vector method.

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

In any ABC, prove that: 2(bosA+ca cos B+ab cos C)=a^(2)+b^(2)+c^(2)